An Improved Method For Retrieving Land Surface Albedo Over Rugged Terrain
Land surface albedo is a very important parameter, which can be derived from a bidirectional reflectance distribution function (BRDF) model with angular integration of BRDF in a particular distribution of downward solar irradiance. The Algorithm for MODIS Bidirectional Reflectance Anisotropic of Land Surface (AMBRALS) utilizes a kernel-driven BRDF model to retrieve land surface albedo, but it does not take into account the topographic effect. This letter proposed an improved method by adding topographic factor to the AMBRALS, which removes the topographic effect on land surface reflectance and considers the topographic effect in retrieving land surface albedo. This method is applied to the HJ-1A/B CCD land surface reflectance data to retrieve the land surface albedo. The results are compared with those from the AMBRALS and with the ground measurements. The comparison results show that the proposed method performs well in general and better than the AMBRALS over rugged area.