VIIRS/NPP Surface Reflectance Daily L2G Global 1km and 500m SIN Grid V001

The 500 meter and 1 kilometer datasets are derived through resampling the native 375 meter and 750 meter VIIRS resolutions, respectively, in the Level 2 input product. These bands are corrected for atmospheric conditions such as the effects of molecular gases, including ozone and water vapor, and for the effects of atmospheric aerosols. The inputs to the surface reflectance algorithm are top-of-atmosphere reflectance for the VIIRS visible bands,the VIIRS cloud mask and aerosol product, aerosol optical thickness and atmospheric data obtained from the NOAA National Centers for Environmental Prediction (NCEP) reanalysis system.

Along with the twelve reflectance bands are reflectance band quality, sensor azimuth angle,solar azimuth angle, sensor zenith angle, solar zenith angle, and observations layers. The reflectance layers from the VNP09GA data product are used as input data for many of the VIIRS land products.

Known Issues

* The VIIRS Land Surface Reflectance product (VNP09) may incorrectly flag retrievals as 'High Aerosol' over brighter surfaces and at higher view angles. This will impact the downstream VIIRS BRDF/Albedo (VNP43) and Vegetation Index (VNP13) data products which use the aerosol quantity flag to screen out high aerosol values.

• Corrections will be implemented in Collection 2 reprocessing in 2022.
• For complete information about known issues please refer to the MODIS/VIIRS Land Quality Assessment website and in Section 4.0 "Caveats and Known Problems" of the User Guide.