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Effects of 3‐D clouds on atmospheric transmission of solar radiation: Cloud type dependencies inferred from A‐train satellite data
Author(s) -
Ham SeungHee,
Kato Seiji,
Barker Howard W.,
Rose Fred G.,
SunMack Sunny
Publication year - 2014
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2013jd020683
Subject(s) - radiance , irradiance , nadir , downwelling , cloud top , shortwave , radiative transfer , infrared window , remote sensing , atmospheric radiative transfer codes , absorption (acoustics) , environmental science , satellite , solar irradiance , atmosphere (unit) , meteorology , optical depth , cloud cover , atmospheric model , cloud fraction , cloud computing , physics , optics , geography , geology , computer science , infrared , astronomy , aerosol , oceanography , upwelling , operating system
Three‐dimensional (3‐D) effects on broadband shortwave top of atmosphere (TOA) nadir radiance, atmospheric absorption, and surface irradiance are examined using 3‐D cloud fields obtained from one hour's worth of A‐train satellite observations and one‐dimensional (1‐D) independent column approximation (ICA) and full 3‐D radiative transfer simulations. The 3‐D minus ICA differences in TOA nadir radiance multiplied by π, atmospheric absorption, and surface downwelling irradiance, denoted as πΔ I , Δ A , and Δ T , respectively, are analyzed by cloud type. At the 1 km pixel scale, πΔ I , Δ A , and Δ T exhibit poor spatial correlation. Once averaged with a moving window, however, better linear relationships among πΔ I , Δ A , and Δ T emerge, especially for moving windows larger than 5 km and large θ 0 . While cloud properties and solar geometry are shown to influence the relationships amongst πΔ I , Δ A , and Δ T , once they are separated by cloud type, their linear relationships become much stronger. This suggests that ICA biases in surface irradiance and atmospheric absorption can be approximated based on ICA biases in nadir radiance as a function of cloud type.