Global albedo, BRDF and nadir BRDF-adjusted reflectance products from MODIS

Abstract

Annual sequences of the first reprocessed Albedo, Bidirectional Reflectance Distribution Function (BRDF), and Nadir BRDF-Adjusted surface Reflectance (NBAR) Products are now being evaluated. BRDF model parameters (or weights) are used to compute black sky albedo at local solar noon and white sky albedo and to compute surface reflectance at a common nadir geometry. In addition to these standard resolution Albedo, BRDF, and NBAR products, which are provided in the Integerized Sinusoidal (ISIN) Grid projection, the BRDF parameters, black sky albedos (at local solar noon), and white sky albedos are now also being operationally produced in a global geographic projection known as the Climate Modeling Grid (CMG). These are currently available at a 0.25 degree spatial resolution, although there is community interest in a 0.05 degree resolution. In addition to the operational CMGs, coarser 0.5 degree and 1 degree resolution versions of the reprocessed albedo data have also been produced for the ISLSCP-II initiative. The global distribution of these albedos (as they vary throughout the year) will be presented, as well as discussions of the most recent evaluations of the quality of the standard products.