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Retrieval of Ice‐Over‐Water Cloud Microphysical and Optical Properties Using Passive Radiometers
Author(s) -
Teng Shiwen,
Liu Chao,
Zhang Zhibo,
Wang Yuan,
Sohn ByungJu,
Yung Yuk L.
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 - 10.1029/2020gl088941
Subject(s) - ice cloud , radiometer , environmental science , remote sensing , cloud computing , liquid water content , shortwave , satellite , cloud fraction , cloud top , optical depth , meteorology , atmospheric sciences , geology , cloud cover , radiative transfer , physics , optics , computer science , aerosol , astronomy , operating system
Current satellite cloud products from passive radiometers provide effective single‐layer cloud properties by assuming a homogeneous cloud in a pixel, resulting in inevitable biases when multiple‐layer clouds are present in a vertical column. We devise a novel method to retrieve cloud vertical properties for ice‐over‐water clouds using passive radiometers. Based on the absorptivity differences of liquid water and ice clouds at four shortwave‐infrared channels (centered at 0.87, 1.61, 2.13, and 2.25 μm), cloud optical thicknesses (COT) and effective radii of both upper‐layer ice and lower‐layer liquid water clouds are inferred simultaneously. The algorithm works most effectively for clouds with ice COT < 7 and liquid water COT > 5. The simulated spectral reflectances based on our retrieved ice‐over‐water clouds become more consistent with observations than those with a single‐layer assumption. This new algorithm will improve our understanding of clouds, and we suggest that these four cloud channels should be all included in future satellite sensors.