Simulation of Brightness Fields of Solar Radiation in the Presence of Optically Anisotropic Ice-Crystal Clouds: Algorithm and Test Results

Abstract

Abstract An original algorithm of statistical simulation of the solar radiative transfer in the presence of ice-crystal clouds, optically anisotropic with respect to the zenith angle of incident radiation, is presented. Examples of preliminarily calculated local optical characteristics of clouds composed of horizontally oriented plates (without accounting for the internal absorption) are given. The software developed was tested within two numerical experiments. The first experiment compared the calculations of reflected radiation for an isotropic medium using the algorithm developed earlier for clouds composed of chaotically oriented particles, and the algorithm presented in this work. The second experiment compared the angular dependence of upward radiation and the scattering phase function in ice-crystal clouds composed of horizontally oriented plates. The numerical experiments indicate that, when this algorithm is used in the radiative transfer simulation, the properties of an optically anisotropic medium are taken adequately into account.