Characterizing Microwave Propagation Using the AFGL Microwave Attenuation/Transmittance/Brightness Temperature Code

A basic research program is described to investigate weather effects on microwave sensors used to remote sounding and to enhance our knowledge of microwave propagation through clouds and precipitation. In this report, we describe the current RADTRAN algorithm, enumerate its deficiencies, and provide corrective solutions. The latter include; (a) updating the code structure providing user friendly menus and internal comments, (b) providing for consistency with standardized input model atmospheres currently implemented within other AFGL transmission/radiance models, (c) undertaking a comparison of the current algorithm with contemporary state-of-the-art transmittance/radiance codes to insure its fidelity and representativeness, (d) enhancing RADTRAN to treat multiple scattering, (e) providing calculations of polarized surface emissivities based on user specified surface types, and (f) document the code. Finally, we describe appropriate statistical retrieval schemes for inclusion in the code so that users can perform sensor simulation/retrieval studies. (RRH)