气候变化领域集成服务门户(CCPortal): Warm early Mars surface enabled by high-altitude water ice clouds

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DOI	10.1073/pnas.2101959118
	Warm early Mars surface enabled by high-altitude water ice clouds
	Kite E.S.; Steele L.J.; Mischna M.A.; Richardson M.I.
发表日期	2021
ISSN	0027-8424
卷号	118 期号:18
英文摘要	Despite receiving just 30% of the Earth's present-day insolation, Mars had water lakes and rivers early in the planet's history, due to an unknown warming mechanism. A possible explanation for the >102-y-long lake-forming climates is warming by water ice clouds. However, this suggested cloud greenhouse explanation has proved difficult to replicate and has been argued to require unrealistically optically thick clouds at high altitudes. Here, we use a global climate model (GCM) to show that a cloud greenhouse can warm a Mars-like planet to global average annual-mean temperature (T) ∼265 K, which is warm enough for low-latitude lakes, and stay warm for centuries or longer, but only if the planet has spatially patchy surface water sources. Warm, stable climates involve surface ice (and low clouds) only at locations much colder than the average surface temperature. At locations horizontally distant from these surface cold traps, clouds are found only at high altitudes, which maximizes warming. Radiatively significant clouds persist because ice particles sublimate as they fall, moistening the subcloud layer so that modest updrafts can sustain relatively large amounts of cloud. The resulting climates are arid (area-averaged surface relative humidity ∼25%). In a warm, arid climate, lakes could be fed by groundwater upwelling, or by melting of ice following a cold-to-warm transition. Our results are consistent with the warm and arid climate favored by interpretation of geologic data, and support the cloud greenhouse hypothesis. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Mars; Paleoclimate; Planetary habitability
语种	英语
scopus关键词	carbon dioxide; ice; surface water; altitude; Article; astronomy; climate warming; cloud; greenhouse; latitude; melting temperature; particle size; polymerization; priority journal; relative humidity; retention time; steady state; topography; water cycle; water supply; water vapor
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/238584
作者单位	Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60615, United States; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, United States; Aeolis Research, Chandler, AZ 85224, United States; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, United States
推荐引用方式 GB/T 7714	Kite E.S.,Steele L.J.,Mischna M.A.,et al. Warm early Mars surface enabled by high-altitude water ice clouds[J],2021,118(18).
APA	Kite E.S.,Steele L.J.,Mischna M.A.,&Richardson M.I..(2021).Warm early Mars surface enabled by high-altitude water ice clouds.Proceedings of the National Academy of Sciences of the United States of America,118(18).
MLA	Kite E.S.,et al."Warm early Mars surface enabled by high-altitude water ice clouds".Proceedings of the National Academy of Sciences of the United States of America 118.18(2021).