The satellite measurements in the visible and near Infrared band are the contribution of surface reflectance and atmospheric back scattering

and it is very difficult to distinguish one form the other for both contribution have the same order over land. The images from high spatial resolution orbit sensor such as TM5 flying on LANDSAT are very clear to discriminate cloud and the shadow since they are projected on the surface from cloud free pixels in the visible hand. Over a nontransparent cloud shadow

the radiance obtained from satellite measurement is the contribution of atmospheric path radiance and surface diffuse reflection; while

over a bright area surrounding the cloud shadow

besides the contribution of atmospheric radiance and surface diffuse reflection

the surface direct reflection also contributes to the radiance measured from satellite. Based on this theory

the difference between the two radiances and its relationship with the surface reflectance and aerosol optical thickness are analyzed

and a new method to retrieve surface reflectance and serosol optical thickness simultaneously over land is developed. At the end of this paper

sensitivity analysis of measurement

single scattering albedo and aerosol scattering phase function to the retrieval of surface reflectance and aerosol optical thickness are given.