Radiative signal received at satellite level over rugged and heterogeneous ground

An algorithm based on the Monte Carlo principle is used to solve completely the radiative transfer problem in the reflective domain over rugged and heterogeneous terrain. This method consists in simulating paths of photons inside the Earth-atmosphere system without introducing analytical modeling and allows to compute the different irradiance terms at ground level and radiance components at sensor level. The potentialities of this method are shown through the evaluation of the different contributions to the total signal received at satellite level over rugged and heterogeneous landscapes. The environment and topographic effects are estimated and simulations show that these contributors which are usually neglected may become very significant. These effects are particularly pronounced over a deep valley covered in part with high reflectance soil like snow. In the shadowed side of this valley, these high order contributors are predominant in the total signal received by the sensor