Evaluation of topographic effects in remotely sensed data

Abstract

Remotely sensed data are generally analyzed assuming flat terrain. As the spectral signature of the ground depends upon the orientation of the surface slope, the topography has to be considered for efficient radiometric corrections in mountainous regions. In this paper, we present a modelization of the atmospheric downward radiance at the ground level which gives us the relative contributions of the direct solar beam and of the diffused radiation for different atmospheric turbidities and different solar incidence angles. Lastly, we estimate the influence of the topography on these contributions to show up which effects can be neglected.