A Numerical Experiment on Chandrasekhar's Discrete-Ordinate Method for Radiative Transfer: Applications to Cloudy and Hazy Atmospheres

Abstract

Abstract The discrete-ordinate method for radiative transfer introduced originally by Chandrasekhar has been theoretically developed and numerically verified for use in solving the transfer of both solar and thermal infrared radiation through cloudy and hazy atmospheres. This method differs from other radiative transfer approaches in the sense that the solution of the transfer equation can be explicitly derived by employing a finite set of discrete-streams representing the emergent angles in the integral term. Hence such a method is practical for deriving a simplified but reliable radiative transfer approximation for meteorological applications involving clouds and aerosols. Comprehensive comparisons with other rigorous means are carried out for the transmitted and reflected intensity and flux associated with isotropic, Rayleigh and anisotropic scattering. The comparisons reveal that close agreement of radiation computations can be achieved by using discrete-streams of 16. For flux calculations, it was fo...