Parameterization of two BRDF models for the retrieval of surface albedo over the Po Valley (Italy) from MISR observations

Earth's surface albedo is an important source of uncertainty in the characterization of atmospheric constituents using radiance measurements. The characterization of the directional behavior of the surface reflectance is also important in the retrieval of atmospheric properties using swapping satellite instruments. The bidirectional reflectance of land surfaces such as vegetation and bare soil, could be represented in terms of a large selection of available physical models. BRDF parameters for RPV and CR models was obtained and broadband albedo calculated from MISR satellite multi-angle radiances. The method is based on the minimization of the difference between measurements and modeled satellite radiance measurements stored in look-up-tables, for different sets of BRDF parameters and atmospheric configurations. Results obtained for the Po Valley region are presented focusing on the period of field campaigns performed in Summer 2007 and Winter 2008 at the rural site San Pietro Capofiume (44.65N, 11.65E).