气候变化领域集成服务门户(CCPortal): The incredible lightness of water vapor

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DOI	10.1175/JCLI-D-19-0260.1
	The incredible lightness of water vapor
	Yang D.; Seidel S.D.
发表日期	2020
ISSN	0894-8755
起始页码	2841
结束页码	2851
卷号	33 期号:7
英文摘要	The molar mass of water vapor is much less than that of dry air. This makes a moist parcel lighter than a dry parcel of the same temperature and pressure. This effect is referred to as the vapor buoyancy effect and has often been overlooked in climate studies. We propose that the vapor buoyancy effect increases Earth's outgoing longwave radiation (OLR) and that this negative radiative effect increases with warming, stabilizing Earth's climate. We illustrate this mechanism in an idealized tropical atmosphere, where there is no horizontal buoyancy gradient in the free troposphere. Temperature increases toward dry atmosphere columns to compensate the reduced vapor buoyancy, increasing OLR by O(1 W m22) at the reference climate. In warmer climates, the temperature difference between moist and dry columns would increase as a result of increasing atmospheric water vapor, leading to enhanced radiative effect and thereby stabilizing Earth's climate. We estimate that this feedback strength is about O(0.2 W m22 K21) in the idealized atmosphere, which compares to cloud feedback and surface albedo feedback in the current climate. We further show evidence from observations and real-gas radiative transfer calculations for a significant radiative effect of vapor buoyancy in the tropical atmosphere. © 2020 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).
英文关键词	Buoyancy; Tropical engineering; Tropics; Water vapor; Atmospheric water vapor; Feedback strength; Outgoing longwave radiation; Radiative transfer calculations; Temperature and pressures; Temperature differences; Temperature increase; Tropical atmospheres; Atmospheric temperature; atmospheric chemistry; buoyancy; climate feedback; longwave radiation; radiative forcing; radiative transfer; temperature profile; tropical meteorology; tropical region; troposphere; water vapor
语种	英语
来源期刊	Journal of Climate
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/171374
作者单位	University of California, Davis, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
推荐引用方式 GB/T 7714	Yang D.,Seidel S.D.. The incredible lightness of water vapor[J],2020,33(7).
APA	Yang D.,&Seidel S.D..(2020).The incredible lightness of water vapor.Journal of Climate,33(7).
MLA	Yang D.,et al."The incredible lightness of water vapor".Journal of Climate 33.7(2020).