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contributor authorZhang, Feng
contributor authorLi, Jiangnan
date accessioned2017-06-09T16:56:01Z
date available2017-06-09T16:56:01Z
date copyright2013/10/01
date issued2013
identifier issn0022-4928
identifier otherams-76661.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4219132
description abstracthough the single-layer solutions have been found for the δ-four-stream spherical harmonic expansion method (SHM) in radiative transfer, there is lack of a corresponding doubling?adding method (4SDA), which enables the calculation of radiative transfer through a vertically inhomogeneous atmosphere with multilayers. The doubling?adding method is based on Chandrasekhar's invariance principle, which was originally developed for discrete ordinates approximation. It is shown that the invariance principle can also be applied to SHM and δ-four-stream spherical harmonic expansion doubling?adding method (δ-4SDA) is proposed in this paper. The δ-4SDA method has been systematically compared to the δ-Eddington doubling?adding method (δ-2SDA), the δ-two-stream discrete ordinates doubling?adding method (δ-2DDA), and δ-four-stream discrete ordinates doubling?adding method (δ-4DDA). By applying δ-4SDA to a realistic atmospheric profile with gaseous transmission considered, it is found that the accuracy of δ-4SDA is superior to δ-2SDA or δ-2DDA, especially for the cloudy/aerosol conditions. It is shown that the relative errors of δ-4SDA are generally less than 1% in both heating rate and flux, while the relative errors of both δ-2SDA and δ-2DDA can be over 6%. Though δ-4DDA is slightly more accurate than δ-4SDA in heating rates, both of them are accurate enough to obtain the cloud-top solar heating. Here δ-4SDA is superior to δ-4DDA in computational efficiency. It is found that the error of aerosol radiative forcing can be up to 3 W m?2 by using δ-2SDA at the top of the atmosphere (TOA); such error is substantially reduced by applying δ-4SDA. In view of the overall accuracy and computational efficiency, δ-4SDA is suitable for application in climate models.
publisherAmerican Meteorological Society
titleDoubling–Adding Method for Delta-Four-Stream Spherical Harmonic Expansion Approximation in Radiative Transfer Parameterization
typeJournal Paper
journal volume70
journal issue10
journal titleJournal of the Atmospheric Sciences
identifier doi10.1175/JAS-D-12-0334.1
journal fristpage3084
journal lastpage3101
treeJournal of the Atmospheric Sciences:;2013:;Volume( 070 ):;issue: 010
contenttypeFulltext


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