The suomi-NPP and jpss albedo, brdf and nbar products have been developed to provide long-term climate-quality continuity with the more than two decades of modis products provided by the terra and…

This federal contract award to the University of Massachusetts Boston (UMass Boston) is focused on the continued maintenance and production of climate quality land surface albedo, bidirectional reflectance distribution function (BRDF), and nadir BRDF-adjusted surface reflectance (NBAR) products from the Suomi-NPP and JPSS (NOAA-20) satellite missions. These products provide essential data on the radiative character of the Earth's land surfaces, which is critical input for climate, weather, hydrologic, and biogeochemical models. The $501,822 grant awarded by the National Science Foundation (NSF) will support UMass Boston's work to extend this long-term data record that was initiated with the MODIS instruments on the Terra and Aqua satellites. The contract does not have any set-aside designation, and UMass Boston is the prime contractor without any major subcontractors mentioned. This effort aligns with NSF's focus on advancing scientific knowledge and providing high-quality observational data to support environmental monitoring and modeling.

The suomi-NPP and jpss albedo, brdf and nbar products have been developed to provide long-term climate-quality continuity with the more than two decades of modis products provided by the terra and aqua missions. Land surface albedo is an essential climate variable (ECV), required by climate, weather, hydrologic, and biogeochemical modelers to quantify the reflective character of land surfaces, and thus estimate the surface radiative forcing. Land surface albedo varies widely in space and time, and is dependent on the land cover, vegetation structure, seasonal phenology, vegetation condition and health, snow cover, and disturbance. The viirs products, from the suomi-NPP and the jpss (currently NOAA-20) missions, provide daily gridded global estimates of this surface variability as both standard products and as lance NRT products. In comparisons with tower albedo data from spatially representative sites, they have been shown to capture the rapid daily variations in albedo caused by ephemeral snowfall and melt, seasonal phenological changes, and disturbance. The intrinsic surface reflectance anisotropy is determined by fitting bidirectional reflectance distribution function (brdf) models to multi-angle cloud-free satellite reflectance observations of each grid location. These brdf estimates, are then integrated hemispherically over all view and illumination geometries to generate intrinsic white sky albedo (bihemispherical reflectance) and over all view angles at a particular solar zenith angle to generate black sky albedo (directional-hemispherical reflectance at local solar noon). The brdf quantities are also used to correct directional surface reflectances to a common view angle (e.g. the nadir brdf-adjusted surface reflectances (nbar) product) and to estimate measures of surface canopy clumping and structure. The standard viirs view-angle-corrected nbar product (provided at local solar noon) are also used to generate downstream viirs phenology products, as well as to monitor the condition of forests, range lands, agricultural fields, and natural ecosystems, and to assess the impact of natural and man-made disturbances (harvest, development, fire, drought, flooding, storm damage etc.). The mature and well documented daily global viirs albedo, brdf, and nbar products are accompanied by extensive quality and uncertainty information and these high-quality products are being embraced by global and regional modeling and monitoring communities to extend the long term record, begun with the modis instruments, into the future. Thus, this effort is focused on the continued maintenance of heritage suomi-NPP and jpss viirs albedo, brdf and nbar products to provide a consistent climate quality record of the radiative character of the earth s land surfaces.