An Analytic Solution of Two-Stream Stochastic Radiative Transfer in Spatially Correlated Media
Hu, Y.X.(a) and Davis, A.B.(b), NASA Langley Research Center (a), Los Alamos National Laboratory (b)
Fourteenth Atmospheric Radiation Measurement (ARM) Science Team Meeting
In situ cloud microphysics measurements show spatial auto-correlations of extinction cross sections over a wide range of scales. At some of those scales, homogeneity and independent-column assumptions fail and a three-dimensional treatment of the radiative transfer is required to capture the effect of the correlations. A simple differential form of transport equation is developed for correlated media in order to account for the first-order impact of the spatial auto-correlations. Two-stream solutions have been derived in closed form from the classic system of mean-field transport equations used to model stochastic radiative transfer in Markovian binary media. They have the proper homogeneous and independent-column limits and have been coded in FORTRAN for fast flux calculations, including both solar and terrestrial radiation. This new analytical result can be used to improve current parameterizations of radiative transfer in partially cloudy GCM cells as well as in diagnostic studies of the atmospheric radiation budget using pathlengths from high-resolution spectroscopy in oxygen bands or lines.
Note: This is the poster abstract presented at the meeting; an extended version was not provided by the author(s).


