NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Two-dimensional radiative transfer in cloudy atmospheres - The spherical harmonic spatial grid methodA new two-dimensional monochromatic method that computes the transfer of solar or thermal radiation through atmospheres with arbitrary optical properties is described. The model discretizes the radiative transfer equation by expanding the angular part of the radiance field in a spherical harmonic series and representing the spatial part with a discrete grid. The resulting sparse coupled system of equations is solved iteratively with the conjugate gradient method. A Monte Carlo model is used for extensive verification of outgoing flux and radiance values from both smooth and highly variable (multifractal) media. The spherical harmonic expansion naturally allows for different levels of approximation, but tests show that the 2D equivalent of the two-stream approximation is poor at approximating variations in the outgoing flux. The model developed here is shown to be highly efficient so that media with tens of thousands of grid points can be computed in minutes. The large improvement in efficiency will permit quick, accurate radiative transfer calculations of realistic cloud fields and improve our understanding of the effect of inhomogeneity on radiative transfer in cloudy atmospheres.
Document ID
19940035530
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Evans, K. F.
(Colorado State Univ. Fort Collins, United States)
Date Acquired
August 16, 2013
Publication Date
September 15, 1993
Publication Information
Publication: Journal of the Atmospheric Sciences
Volume: 50
Issue: 18
ISSN: 0022-4928
Subject Category
Meteorology And Climatology
Accession Number
94A12185
Funding Number(s)
CONTRACT_GRANT: NAG5-1592S-02
CONTRACT_GRANT: DE-FG02-90ER-61067
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available