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m Added detail to bio of AGU Fellow, following up on previous edit by 67.182.136.209
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Catling also contributed to the first measurements of Earth's atmospheric thickness billions of years ago. He helped pioneer two techniques: using fossil raindrop imprints to set an upper limit on air density, which was applied to fossil imprints from 2.7 billion years ago,<ref>{{cite journal|last1=Som|first1=S. M.|last2=Catling|first2=D. C.|last3=Harnmeijer|first3=J. P.|last4=Polivka|first4=P. M.|last5=Buick|first5=R.|s2cid=4410348|title=Air density 2.7 billion years ago limited to less than twice modern levels by fossil raindrop imprints|journal=Nature|date=2012|volume=484|issue=7394|pages=359–362|doi=10.1038/nature10890|pmid=22456703|bibcode=2012Natur.484..359S}}</ref><ref>{{Cite web|url=https://www.pbs.org/newshour/rundown/what-a-cake-pan-hairspray-taught-us-about-earths-ancient-atmosphere/|title=What a Baking Pan and Hairspray Taught Us About Earth's Ancient Atmosphere|last=Marder|first=Jenny|date=2012|website=PBS Newshour|language=en-US|access-date=2016-08-21}}</ref> and using fossil bubbles in ancient lava flows, which suggests that air pressure 2.7 billion years ago was less than half that of the modern atmosphere.<ref>{{Cite journal|last1=Som|first1=S. M.|last2=Buick|first2=R.|last3=Hagadorn|first3=J. W.|last4=Blake|first4=T. S.|last5=Perrault|first5=J. M.|last6=Harnmeijer|first6=J. P.|last7=Catling|first7=D. C.|s2cid=4662435|date=2012|title=Earth's air pressure 2.7 billion years ago constrained to less than half of modern levels|journal=Nature Geoscience|volume=9|issue=6|pages=448–451|doi=10.1038/ngeo2713|bibcode=2016NatGe...9..448S}}</ref><ref>{{Cite news|date=May 14–20, 2012|title=The curious lightness of an early atmosphere|url=https://www.economist.com/news/science-and-technology/21698640-two-new-studies-suggest-young-earth-may-have-been-even-less-todays|newspaper=The Economist|volume=419|issue=8989|pages=69–70}}</ref>
Catling has also researched the evolution of the atmosphere and surface of Mars.<ref>{{cite book|last1=Catling|first1=David C.|editor1-last=Spohn|editor1-first=T.|editor2-last=Breuer|editor2-first=D.|editor3-last=Johnson|editor3-first=T. V.|title=Encyclopedia of the Solar System|publisher=Elsevier|location=Amsterdam|isbn=9780124158450|pages=343–357|edition=Third|chapter=Mars Atmosphere: History and Surface Interactions|date=2014-08-04}}</ref> In the 1990s, he pioneered research on how the types of salts from dried-up lakes or seas on Mars could indicate the past environment and whether Mars was habitable.<ref>{{cite journal|last1=Catling|first1=D. C.|s2cid=129783260|title=A chemical model for evaporites on early Mars: Possible sedimentary tracers of the early climate and implications for exploration|journal=Journal of Geophysical Research|date=1999|volume=104|issue=E7|pages=16,453–16,470|doi=10.1029/1998JE001020|bibcode=1999JGR...10416453C|doi-access=free}}</ref> Since then, the discovery of salts and clays from former lakebeds has been a key success of missions to Mars by NASA and [[European Space Agency|ESA]]. Catling was on the Science Team for NASA's [[Phoenix Lander]] mission, which in 2008 was the first spacecraft to land in the ice-rich high latitudes of Mars. Catling contributed to research that included the first scoops by a lander of water ice from below the surface of Mars<ref>{{cite journal|last1=Smith|first1=P. H.|last2=Tamppari|first2=L.|last3=Arvidson|first3=R. E.|last4=Bass|first4=D. S.|last5=Blaney|first5=D.|author5-link= Diana Blaney |last6=Boynton|first6=W. V.|last7=Carswell|first7=A.|last8=Catling|first8=D. C.|title=H2O at the Phoenix landing site|journal=Science|date=2009|volume=325|issue=5936|pages=58–61|doi=10.1126/science.1172339|display-authors=etal|pmid=19574383|bibcode=2009Sci...325...58S|s2cid=206519214 }}</ref> and the first measurement of soluble salts in martian soil, including the [[soil pH]].<ref>{{cite journal|last1=Hecht|first1=M. H.|last2=Kounaves|first2=S. P.|last3=Quinn|first3=R. C.|last4=West|first4=S. J.|last5=Young|first5=S. M. M.|last6=Ming|first6=D. W.|last7=Catling|first7=D. C.|last8=Clark|first8=B. C.|last9=Boynton|first9=W. V.|last10=Hoffman|first10=J.|last11=DeFlores|first11=L. P.|last12=Gospodinova|first12=K.|last13=Kapit|first13=J.|last14=Smith|first14=P. H.|s2cid=24299495|title=Detection of perchlorate and soluble chemistry of martian soil: Findings from the Phoenix Mars Lander|journal=Science|date=2009|volume=325|issue=5936|pages=64–67|doi=10.1126/science.1172466|pmid=19574385|bibcode=2009Sci...325...64H}}</ref> In experimental work with Jonathan Toner to examine low-temperature solutions of [[perchlorate]] salts, as found on Mars, Toner and Catling discovered that such solutions super cool and never crystallize.<ref>{{cite journal|last1=Toner|first1=J. D.|last2=Catling|first2=D. C.|last3=Light|first3=B.|title=The formation of supercooled brines, viscous liquids, and low-temperature glasses on Mars|journal=Icarus|date=2014|volume=233|pages=36–47|doi=10.1016/j.icarus.2014.01.018|bibcode=2014Icar..233...36T}}</ref> The perchlorates form glasses ([[amorphous solids]]) around -120 °C. Glasses are known to be far better for preserving microbes and biological molecules than crystalline salts, which could be relevant to the search for [[life on Mars]], Jupiter's moon [[Europa (moon)|Europa]], and Saturn's moon [[Enceladus]].
In the field of planetary atmospheres, David Catling and Tyler Robinson proposed a general explanation for a curious observation: the minimum air temperature between the [[troposphere]] (the lowest atmospheric layer where temperature declines with altitude) and [[stratosphere]] (where temperature increases with altitude in an '[[Inversion (meteorology)|inversion]]') occurs a pressure of about 0.1 bar on Earth, Titan, Jupiter, Saturn, Uranus, and Neptune. This level is the [[tropopause]]. Robinson and Catling used the physics of radiation to explain why the tropopause temperature minimum in these extremely different atmospheres occurs at a common pressure.<ref>{{cite journal|last1=Robinson|first1=T. D.|last2=Catling|first2=D. C.|title=Common 0.1 bar tropopause in thick atmospheres set by pressure-dependent infrared transparency|journal=Nature Geoscience|date=2014|volume=7|issue=1|pages=12–15|doi=10.1038/NGEO2020|arxiv=1312.6859|bibcode=2014NatGe...7...12R|s2cid=73657868 }}</ref> They propose that pressure around 0.1 bar could be a fairly general rule for planets with stratospheric temperature inversions. This rule could constrain the atmospheric structure of exoplanets and hence their surface temperature and habitability.
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