The NPP/VIIRS surface reflectance products are estimates of surface reflectance in each of the VIIRS reflective bands I1-I3, M1-M5, M7, M8, M10, and M11. VNP09GA is a Level-2G surface reflectance product produced on a 10km x 10km grid. The VNP09GA surface reflectance product is composed of all available surface reflectance observations for a given day over a set of tiles with global coverage. The tile numbering scheme and boundaries are the same as for MODIS. The first set of observations for each data set and grid cell are projected onto a two-dimensional grid and stored as 10km square tiles at 500m and 1 km resolution.
Surface reflectance is obtained by adjusting top-of-atmosphere reflectance to compensate for atmospheric effects. Corrections are made for the effects of molecular gases, including ozone and water vapor, and for the effects of atmospheric aerosols. The inputs to the surface reflectance algorithm include top-of-atmosphere reflectance for the VIIRS visible bands (VNP02MOD, VNP02IMG), the VIIRS cloud mask and aerosol product (NPP-CMIP_L2), aerosol optical thickness (NPP_VAOTIP_L2, NPP_VAMIP_L2), and atmospheric data obtained from a reanalysis (surface pressure, atmospheric precipitable water, and ozone concentration).
All surface reflectance products are produced for daytime conditions only. The product is produced under all atmospheric conditions except for night and oceans. Pixels when not produced are replaced by fill values in the Level-2 and Level-2G products.
||375 m, 500 m, 750 m, 1 km
||NPP VIIRS collection 1.0 (ArchiveSet 5000)
|File Naming Convention:
- AYYYYDDD = Acquisition Year and Day of Year
- hHH = Horizontal tile number (0-71)
- vVV = Vertical tile number (0-71)
- CCC = Collection number
- YYYYDDDHHMMSS = Production Date and Time
- hdf = Hierarchical Data Format
||Climate Change, Reflectance, Atmospheric Correction, Aerosol Optical Depth/Thickness