Passive spaceborne imagers observe radiation that has interacted both with the atmosphere and the surface. Interactions with the atmosphere include gaseous absorption and scattering by molecules and particulate matter or aerosols. Their characterization from remote sensing observations relies essentially on their capacity to modify differently the amount of radiation observed as a function of the wavelength, the viewing directions or the polarization. One of the major issues when retrieving tropospheric aerosol properties using spaceborne imager observations is to discriminate the contribution of the observed signal reflected by the surface from the one scattered and absorbed by the aerosols. In particular, it is crucial when the retrieval occurs above land surfaces which might be responsible for a non-negligible part of the total signal. Conceptually, this is equivalent to solving a radiative system composed of minimum two layers, where the upper layers includes aerosols and the bottom ones represents the soil/vegetation strata. This problem is further complicated by the intrinsic anisotropic radiative behavior of natural surfaces and its coupling with atmospheric radiative processes. An increase in aerosol optical thickness is responsible for an increase of the fraction of diffuse sky radiation which, in turn, smooths the effects of surface anisotropy.