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Seasonal Dependent Impact of Ice Cloud Longwave Scattering on the Polar Climate
Author(s) -
Chen YiHsuan,
Huang Xianglei,
Yang Ping,
Kuo ChiaPang,
Chen Xiuhong
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl090534
Subject(s) - longwave , sea ice , atmospheric sciences , environmental science , scattering , atmosphere (unit) , ice albedo feedback , climate model , climatology , polar , outgoing longwave radiation , cryosphere , radiative transfer , geology , meteorology , physics , climate change , sea ice thickness , astronomy , oceanography , optics , convection , quantum mechanics
Abstract Most climate models neglect cloud longwave (LW) scattering because scattering is considered negligible compared to strong LW absorption by clouds and greenhouse gases. While this rationale is valid for simulating extrapolar regions, it is questionable for the polar regions, where the atmosphere is dry and hence has weak absorption, and ice clouds that have strong scattering capability frequently occur. Using the slab‐ocean Community Earth System Model, we show that ice cloud LW scattering can warm winter surface air temperature by 0.8–1.8 K in the Arctic and 1.3–1.9 K in the Antarctic, while this warming becomes much weaker in polar summer. Such scattering effect cannot be correctly assessed when sea surface temperature and sea ice are prescribed as this effect is manifested through a surface‐atmosphere coupling. Cloud LW scattering is a necessity for the correct simulation of polar climate and surface radiation budget, especially in the winter.