气候变化领域集成服务门户(CCPortal): Impact of Subgrid Variation of Water Vapor on Longwave Radiation in a General Circulation Model

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DOI	10.1029/2019MS001926
	Impact of Subgrid Variation of Water Vapor on Longwave Radiation in a General Circulation Model
	Kim S.; Park S.; Shin J.
发表日期	2020
ISSN	19422466
卷号	12 期号:4
英文摘要	Most general circulation models compute radiation fluxes by assuming that water vapor is uniform within individual grid layers, which leads to an underestimation of satellite-observed longwave (LW) cloud radiative forcing (LWCF). To fix this problem, we calculated water vapor content separately for clear and cloudy portions and used them to compute LW radiation. The impacts of this modification were examined by comparing two global simulations with and without the modification (NEW and OLD, respectively). Global-annual mean LWCF from NEW was 1.8 W m−2 higher than that of OLD, thus remedying a long-standing negative bias of LWCF. This improvement is a combined result of more clear-sky and less all-sky upward LW flux at the top of the atmosphere than OLD. Large increases in LWCF and clear-sky LW flux occurred in the tropical deep convection and midlatitude storm track regions where upper- and middle-level clouds are abundant. Although only the LW radiation scheme was modified, global-annual mean shortwave cloud radiative forcing also increased, particularly in the vicinity of the eastern subtropical marine stratocumulus decks through radiative feedback processes. With this improved treatment, it may be possible to tune general circulation models in a more flexible and physical way without introducing compensating errors. ©2020. The Authors.
英文关键词	GCM; longwave cloud radiative forcing; longwave radiation; water vapor inhomogeneity
语种	英语
scopus关键词	Atmospheric radiation; Climate models; Tropics; Cloud radiative forcing; Compensating errors; General circulation model; Long-wave radiation; Marine stratocumulus; Mid-latitude storms; Top of the atmospheres; Water vapor contents; Water vapor; atmospheric convection; cloud radiative forcing; estimation method; general circulation model; longwave radiation; storm track; stratocumulus; top of atmosphere; water vapor
来源期刊	Journal of Advances in Modeling Earth Systems
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/156720
作者单位	School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea
推荐引用方式 GB/T 7714	Kim S.,Park S.,Shin J.. Impact of Subgrid Variation of Water Vapor on Longwave Radiation in a General Circulation Model[J],2020,12(4).
APA	Kim S.,Park S.,&Shin J..(2020).Impact of Subgrid Variation of Water Vapor on Longwave Radiation in a General Circulation Model.Journal of Advances in Modeling Earth Systems,12(4).
MLA	Kim S.,et al."Impact of Subgrid Variation of Water Vapor on Longwave Radiation in a General Circulation Model".Journal of Advances in Modeling Earth Systems 12.4(2020).