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A Solar Radiation Parameterization for Atmospheric StudiesThe solar radiation parameterization (CLIRAD-SW) developed at the Goddard Climate and Radiation Branch for application to atmospheric models are described. It includes the absorption by water vapor, O3, O2, CO2, clouds, and aerosols and the scattering by clouds, aerosols, and gases. Depending upon the nature of absorption, different approaches are applied to different absorbers. In the ultraviolet and visible regions, the spectrum is divided into 8 bands, and single O3 absorption coefficient and Rayleigh scattering coefficient are used for each band. In the infrared, the spectrum is divided into 3 bands, and the k-distribution method is applied for water vapor absorption. The flux reduction due to O2 is derived from a simple function, while the flux reduction due to CO2 is derived from precomputed tables. Cloud single-scattering properties are parameterized, separately for liquid drops and ice, as functions of water amount and effective particle size. A maximum-random approximation is adopted for the overlapping of clouds at different heights. Fluxes are computed using the Delta-Eddington approximation.
Document ID
Acquisition Source
Goddard Space Flight Center
Document Type
Technical Memorandum (TM)
Chou, Ming-Dah
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Suarez, Max J.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
September 6, 2013
Publication Date
June 1, 1999
Subject Category
Report/Patent Number
NAS 1.15:104606/VOL15
Distribution Limits
Work of the US Gov. Public Use Permitted.
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