Comparison Study of the BLITS and BLIRB Radiative Transport Models

Abstract : This report is one in a series of volumes that document the Weather and Atmospheric Visualization Effects for Simulation (WAVES) suite of models. Each volume describes an aspect of the series of models. This particular report documents a comparison of the surface-based radiative transport (RT) code Boundary Layer Illumination and Transmission for Simulation (BLITS) with the volumetric RT code for Boundary Layer Illumination and Radiation Balance (BLIRB). This comparison is made using a simple three-dimensional (3-D) scenario that consists of a homogeneous cubical cloud filled with an aerosol described by the Deirmendjian type C.1 cloud phase function. Comparisons of the two RT models are made relative to results from two separate but consistent Monte Carlo models. For this simple scenario, BLIRB was determined to perform better than BLITS for the complete range of optical depths used. The BLITS model failed to accurately describe the radiant intensity of the scattering in the atmosphere at low optical depths.