Equations for Estimating the Similarity Parameter from Radiation Measurements within Weakly Absorbing Optically Thick Clouds

Abstract

Series expansions are derived for estimating the similarity parameter, which is a combination of the single-scattering albedo and asymmetry factor, from radiance measurement deep in the interior of a weary absorbing cloud. One expansion requires the measurements of the radiance in only the zenith and nadir directions, while a second uses the downward and upward irradiances. Numerical calculations show the estimates for the similarity parameter are very insensitive to different values of the asymmetry factor.