A Numerical Model of Thermal Radiation in a Dusty Atmosphere

Abstract

Abstract A method is presented for numerically calculating the infrared radiative fluxes in a dusty atmosphere: a multicomponent planar medium which absorbs, emits, and anisotropically scatters radiation. The method utilizes number of different solutions, depending on the particular monochromatic properties of the medium. The most general solution, including dust and gas absorption and dust scatter, is an iterative numerical integration of the system of simultaneous differential equations for the intensity. If scattering is relatively unimportant in a particular spectral region, the equations are uncoupled from one another and a non-iterative numerical integration is used. In spectral regions with very strong gaseous absorption, the optically thick limit is employed. Elsasser's band-averaged gas transmissivities are represented by a weighted sum of exponential functions of optical path. This model provides gas absorption coefficients which may be treated as constant over specified fractions of a band. The...