Distribution of radiative energy in ground fog

Abstract

This study deals with the distribution of solar and infrared radiation in a multiple scattering and absorbing fog consisting of water droplets and water vapor. An iterative solution of the radiative transfer equation, as formulated by Chandrasekhar (1960), is presented here, which is utilized to obtain radiative intensities, fluxes and their vertical divergence for the entire infrared spectrum. A sufficient number of sample computations is carried out also in the solar spectrum such as to verify the applicability of the numerical procedure for the entire heat spectrum. All calculations are made for two fog models, representing low and high fog for a liquid cloud water concentration of 0.1 g per cubic meter. The exact structure of spectral lines is taken into account. Computational results verify the applicability of the method for the entire spectrum for a fog extending to a height of at least 160 m. It is believed that the computational procedure as developed is capable also of obtaining information about the radiative behavior of clouds and fogs of far greater thickness.