气候变化领域集成服务门户(CCPortal): Reassessment of shortwave surface cloud radiative forcing in the Arctic: Consideration of surface-albedo-cloud interactions

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DOI	10.5194/acp-20-9895-2020
	Reassessment of shortwave surface cloud radiative forcing in the Arctic: Consideration of surface-albedo-cloud interactions
	Stapf J.; Ehrlich A.; Jäkel E.; Lüpkes C.; Wendisch M.
发表日期	2020
ISSN	1680-7316
起始页码	9895
结束页码	9914
卷号	20 期号:16
英文摘要	The concept of cloud radiative forcing (CRF) is commonly applied to quantify the impact of clouds on the surface radiative energy budget (REB). In the Arctic, specific radiative interactions between microphysical and macrophysical properties of clouds and the surface strongly modify the warming or cooling effect of clouds, complicating the estimate of CRF obtained from observations or models. Clouds tend to increase the broadband surface albedo over snow or sea ice surfaces compared to cloud-free conditions. However, this effect is not adequately considered in the derivation of CRF in the Arctic so far. Therefore, we have quantified the effects caused by surface-albedo-cloud interactions over highly reflective snow or sea ice surfaces on the CRF using radiative transfer simulations and below-cloud airborne observations above the heterogeneous springtime marginal sea ice zone (MIZ) during the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign. The impact of a modified surface albedo in the presence of clouds, as compared to cloud-free conditions, and its dependence on cloud optical thickness is found to be relevant for the estimation of the shortwave CRF. A method is proposed to consider this surface albedo effect on CRF estimates by continuously retrieving the cloud-free surface albedo from observations under cloudy conditions, using an available snow and ice albedo parameterization. Using ACLOUD data reveals that the estimated average shortwave cooling by clouds almost doubles over snow-and ice-covered surfaces (-62 Wm-2 instead of-32 Wm-2), if surface-albedo-cloud interactions are considered. As a result, the observed total (shortwave plus longwave) CRF shifted from a warming effect to an almost neutral one. Concerning the seasonal cycle of the surface albedo, it is demonstrated that this effect enhances shortwave cooling in periods when snow dominates the surface and potentially weakens the cooling by optically thin clouds during the summertime melting season. These findings suggest that the surface-albedo-cloud interaction should be considered in global climate models and in long-term studies to obtain a realistic estimate of the shortwave CRF to quantify the role of clouds in Arctic amplification. © 2020 Author(s).
语种	英语
scopus关键词	albedo; cloud microphysics; cloud radiative forcing; conceptual framework; energy budget; parameterization; quantitative analysis; radiative transfer; shortwave radiation; Arctic
来源期刊	Atmospheric Chemistry and Physics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/141137
作者单位	Leipzig Institute for Meteorology (LIM), University of Leipzig, Leipzig, Germany; Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
推荐引用方式 GB/T 7714	Stapf J.,Ehrlich A.,Jäkel E.,et al. Reassessment of shortwave surface cloud radiative forcing in the Arctic: Consideration of surface-albedo-cloud interactions[J],2020,20(16).
APA	Stapf J.,Ehrlich A.,Jäkel E.,Lüpkes C.,&Wendisch M..(2020).Reassessment of shortwave surface cloud radiative forcing in the Arctic: Consideration of surface-albedo-cloud interactions.Atmospheric Chemistry and Physics,20(16).
MLA	Stapf J.,et al."Reassessment of shortwave surface cloud radiative forcing in the Arctic: Consideration of surface-albedo-cloud interactions".Atmospheric Chemistry and Physics 20.16(2020).