AN IMPROVED BIDIRECTIONAL REFLECTANCE DISTRIBUTION FUNCTION (BRDF) OVER RUGGED TERRAIN BASED ON MODERATE SPATIAL RESOLUTION REMOTE SENSING DATA

Land surface albedo is derived from a bidirectional reflectance distribution function (BRDF) model with angular integration of BRDF. The kernel-driven model is based on the Algorithm for MODIS Bidirectional Reflectance Anisotropic of Land Surface (AMBRALS) to retrieve land surface albedo. However, at moderate/low spatial resolution scale, topography results in mutual shading of sub-pixels, the kernel-driven model does not deal explicitly with such topographic effects. This paper proposes an improved kernel-driven model by adding a topographic factor to the kernel-driven model. This model was applied to MODIS land surface reflectance and the results were compared with the ones obtained with AMBRALS. The results were evaluated against ground measurements.