Description
The NOAA-20 Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) Bidirectional Reflectance Distribution Function (BRDF) and Albedo Model Parameters (VJ143DNBA1) Version 2 product provides BRDF/Albedo model parameters at 1 kilometer (km) resolution. The VJ143DNBA1 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 VJ143 data products are designed to promote the continuity of NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) BRDF/Albedo data product suite.
The VJ143 algorithm uses the RossThick/Li-Sparse-Reciprocal (RTLSR) semi-empirical kernel-driven BRDF model, with the three kernel weights from VJ143DNBA1 to reconstruct surface anisotropic effects, correcting the directional reflectance to a common view geometry (VJ143DNBA4), while also computing integrated black-sky albedo (BSA) at local solar noon and white-sky albedo (WSA) (VJ143DNBA3). 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) layers 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 VJ143DNBA1 data product provides two SDS layers for mandatory quality and model parameters representing fiso, fvol, and fgeo for the VIIRS DNB. A low-resolution browse is also available showing BRDF/Albedo parameters for the DNB as a red, green, blue (RGB) image in JPEG format.
Known Issues
- For complete information about known issues please refer to the MODIS/VIIRS Land Quality Assessment website.
Improvements/Changes from Previous Version
- The NOAA-20 VIIRS algorithms include the same improvements as the S-NPP VIIRS V002
- Improved calibration algorithm and better coefficients for entire NOAA-20 mission
- Improved geolocation accuracy and updates to fix outliers around maneuver periods and other events
- Corrections to the aerosol quantity flag (low, average, high) mainly over brighter surfaces in the mid to high latitudes such as desert and tropical vegetation areas. This has an impact on the retrieval of other downstream data products such as VJ113 Vegetation Indices and VJ143 BRDF/Albedo.
- Improved cloud mask input product for corrections along coastlines and artifacts from use of coarse resolution climatology data
- Replaced the land/water mask input product with MODIS heritage seven class land/water mask
Product Summary
Citation
Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.
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Documents
ALGORITHM THEORETICAL BASIS DOCUMENT (ATBD) | The ATBD provides physical theory and mathematical procedures for the calculations used to produce the data products. | |
GENERAL DOCUMENTATION | The File Specification provides a description of the product file including Scientific Data Sets and their attributes. | |
PRODUCT QUALITY ASSESSMENT | The LDOPE Land Product Quality Assessment website provides known issues, maneuvers, and product quality of the land products. | |
SCIENCE DATA PRODUCT VALIDATION | Validation at stage 3 has been achieved for the VIIRS BRDF/Albedo product suite. | |
SCIENCE DATA PRODUCT VALIDATION | Further details regarding VIIRS product validation and maturity status are available from VIIRS Land Product Quality Assessment site. |