Effectiveness of the MS-method for computation of the intensity field reflected by a multi-layer plane-parallel atmosphere

A radiative transfer code based on the coupling of the currently labeled MS method (MS refers to the separation of the multiply and singly scattered radiation), with the reliable and widely used radiative transfer package DISORT is presented. We show that this code can be used to compute the intensity field reflected by a plane-parallel, non-emitting, aerosol loaded atmosphere with the same accuracy as a non-approximate model but maintaining a high computational speed. Results obtained for a two-layer atmosphere show that the single scattering features are clearly visible in the radiative field in the range from moderate to high aerosol optical thicknesses. Tests carried out in a reasonable range of viewing geometries, restricted to dark surfaces, and considering a significant set of aerosol optical properties, have shown that the present code is capable of attaining the same accuracy as DISORT but using a greatly decreased number of angular discretizations (streams), thereby reducing the computational time by a factor of between 2 and 10 with respect to DISORT. depending on the complexity of the scenario. (C) 2001 Elsevier Science Ltd. All rights reserved.