Approximation of Topographic Effect on Atmospheric Correction in Rugged Terrain

Abstract

The surface radiance distribution measured from space differs from its value at the ground, because of the presence of the atmosphere. The multidimensional theory of radiative transfer in terrestrial atmosphere plays an important role in atmospheric correction for image processing not only in flat terrain but also in rugged terrain. In the present paper it is shown how to solve approximately and effectively the transfer equation in rugged terrain. It is physically approximated by the global approach; (i) the effect of terrain orientation, consisting of the direct and diffuse radiation in connection with shadow, (ii) the irradiance effect from the adjacent terrain, and others. Such physical reduction seems to be tractable so that the simultaneous solution of the nonlinear Riccati-type integrodifferential equations governing the scattering and transmission functions with the topography-dependent boundary conditions is numerically carried out via the high-speed digital computers.