Multidecadal MODIS and VIIRS Climate Products

The latest reprocessed (V006) MODerate resolution Imaging Spectroradiometer (MODIS) daily albedo products (from 2000 to present) are now available for modeling studies. The products are provided in a variety of formats, from 10degree tiles of 500m gridded data in a sinusoidal projection (MCD43A) to global 30arc second gridded data in a geographic lat/lon projection (MCD43D), with 0.05degree gridded averages also available (MCD43C) for climate studies. These clear sky, multi-decadal products include intrinsic surface albedos (a diffuse white-sky albedo, or bihemispherical reflectance, and a direct component black-sky albedo, or directional-hemispherical reflectance, at the solar zenith angle of local solar noon) and a Nadir BRDF-Adjusted Reflectance (NBAR) which is a view angle corrected reflectance at local solar noon. The Bidirectional Reflectance Distribution Function (BRDF) model parameters, which are retrieved at each grid point and used to produce the albedo and NBAR quantities, are also provided so that users can generate black-sky albedo and NBAR values at any desired solar zenith angle. These various products are generated for both individual spectral bands and for three broadbands (0.3-0.7µm, 0.7-5.0µm, and 0.3-5.0µm). All of these products are accompanied by extensive quality flags describing the per-band quality of the BRDF retrieval and indicating whether the albedo retrieved is of a snow or snow free location. While these products represent clear sky intrinsic surface albedos (governed by the land surface characteristics and without consideration of the atmospheric scattering effects), actual blue-sky albedos can be generated for a location by combining the black-sky albedo and the white-sky albedo as a function of aerosol optical depth at a particular point in time (i.e. a particular solar zenith angle). However, it should be noted that these blue-sky albedos are cloud free quantities. These MODIS blue-sky albedo values are periodically assessed against spatially representative tower based albedo measures (such as from the Baseline Surface Radiation Network, BSRN) and the various MODIS products have been used extensively for initialization of global climate and biogeochemical models, surface vegetation and disturbance monitoring, and assessment of surface energy budget model results. While the MODIS instruments on board the NASA Terra and Aqua satellites are nearing the end of their lifetimes, comparable products (VNP43) are now being produced from the Visible Infrared Imaging Radiometer Suite (VIIRS) instruments on board the NOAA Suomi NPP and JPSS satellites. These VIIRS products allow for the continuation of multi-decadal BRDF, Albedo, and NBAR products for climate studies into the future.