The NOAA-21 Visible Infrared Imaging Radiometer Suite (VIIRS) Bidirectional Reflectance Distribution Function (BRDF) and Albedo (VJ243MA3) Version 2 product provides albedo values at 1 kilometer (km) resolution for the bihemispherical reflectance white-sky albedo (WSA) and directional hemispherical reflectance black-sky albedo (BSA) at local solar noon. The VJ243MA3 product is produced daily using 16 days of VIIRS data and is weighted temporally to the ninth day, which is reflected in the file name. The VJ243 data products are designed to promote the continuity of NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) BRDF/Albedo data product suite.
The VJ243 algorithm uses the RossThick/Li-Sparse-Reciprocal (RTLSR) semi-empirical kernel-driven BRDF model, with the three kernel weights from (VJ243MA1) to reconstruct surface anisotropic effects, correcting the directional reflectance to a common view geometry (VJ243MA4), while also computing integrated black-sky albedo (BSA) at local solar noon and white-sky albedo (WSA) (VJ243MA3). Researchers can use the BRDF model parameters with a simple polynomial, to obtain black-sky albedo at any solar illumination angle. Likewise, both the BSA and WSA Science Dataset (SDS) variables can be used with a simple polynomial, to manually estimate instantaneous actual albedo (blue-sky albedo). Additional details regarding the methodology are available in the Algorithm Theoretical Basis Document (ATBD).
The VJ243MA3 product provides a total of 36 SDS variables including: BSA; WSA; and mandatory quality variables for nine VIIRS moderate bands M1-M5, M7-M8, and M10-M11; as well as near-infrared (NIR); shortwave; and visible broadbands. A low-resolution image is also available showing retrievals of WSA for band M1 in JPEG format.
Known Issues
* For complete information about known issues please refer to the MODIS/VIIRS Land Quality Assessment website.