VIIRS/NPP Photosynthetically Active Radiation Daily L3 Global 0.05Deg CMG V002

The delivery of all Suomi National Polar-orbiting Partnership (Suomi NPP) VIIRS science data products will cease on November 2, 2026 (2026/306). Data users are encouraged to transition to the equivalent VJ218A2 (primary) or VJ118A2 (secondary) data products. The VNP18A2 Version 2 is a NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) Photosynthetically Active Radiation (PAR) gridded Level 3 product. It is produced at 1 kilometer pixel resolution at daily intervals. PAR is the incident solar radiation in the visible spectrum (400-700 nanometers) and is a significant variable in land surface models (LSMs), receiving increased attention due to its importance for the management and operation of solar energy systems. The VNP18 algorithm adapts the narrowband look-up table (LUT) approach to estimate PAR. The LUTs consider different types of loadings of aerosols and clouds at a variety of illumination and viewing geometry. The Algorithm Theoretical Basis Document (ATBD) is forthcoming and will provide additional details regarding the methodology used to create the data. Provided in the VNP18A2 product are variables for instantaneous total, direct, and diffuse PAR, as well as 3-hour PAR, daily mean PAR, and a quality variable.

The delivery of all Suomi National Polar-orbiting Partnership (Suomi NPP) VIIRS science data products will cease on November 2, 2026 (2026/306). Data users are encouraged to transition to the equivalent VJ218C1 (primary) or VJ118C1 (secondary) data products. The VNP18C1 Version 2 is a NASA/NOAA Suomi National Polar-Orbiting Partnership (Suomi NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) Downward Shortwave Radiation (DSR) Level 3 Climate Modeling Grid (CMG) product. It is produced at 0.05 degree pixel resolution at daily intervals. DSR is the incident solar radiation over land surfaces in the shortwave spectrum (300-4,000 nanometers) and is a significant variable in land surface models (LSMs), receiving increased attention due to its importance for the management and operation of solar energy systems. The VNP18 algorithm adapts the narrowband look-up table (LUT) approach to estimate DSR. The LUTs consider different types of loadings of aerosols and clouds at a variety of illumination and viewing geometry. The Algorithm Theoretical Basis Document (ATBD) is forthcoming and will provide additional details regarding the methodology used to create the data. The VNP18C1 product is aggregated from VNP18A1 files and includes one set of global 3-hour DSR variables and daily mean DSR.

The NOAA-20 Visible Infrared Imaging Radiometer Suite (VIIRS) Photosynthetically Active Radiation (PAR) Level 3 Climate Modeling Grid (CMG) product produced at 0.05 degree pixel resolution at daily intervals. PAR is the incident solar radiation in the visible spectrum (400-700 nanometers) and is a significant variable in land surface models (LSMs), receiving increased attention due to its importance for the management and operation of solar energy systems. The VJ118 algorithm adapts the narrowband look-up table (LUT) approach to estimate PAR. The LUTs consider different types of loadings of aerosols and clouds at a variety of illumination/viewing geometry. The Algorithm Theoretical Basis Document (ATBD) is forthcoming and will provide additional details regarding the methodology used to create the data. The VJ118C2 product is aggregated from VJ118A2 files and includes one set of global 3-hour PAR variables and one set of daily mean PAR.

The NOAA-21 Visible Infrared Imaging Radiometer Suite (VIIRS) Photosynthetically Active Radiation (PAR) Level 3 Climate Modeling Grid (CMG) product produced at 0.05 degree pixel resolution at daily intervals. PAR is the incident solar radiation in the visible spectrum (400-700 nanometers) and is a significant variable in land surface models (LSMs), receiving increased attention due to its importance for the management and operation of solar energy systems. The VJ218 algorithm adapts the narrowband look-up table (LUT) approach to estimate PAR. The LUTs consider different types of loadings of aerosols and clouds at a variety of illumination/viewing geometry. The Algorithm Theoretical Basis Document (ATBD) is forthcoming and will provide additional details regarding the methodology used to create the data. The VJ218C2 product is aggregated from VJ218A2 files and includes one set of global 3-hour PAR variables and one set of daily mean PAR. Known Issues * For complete information about known issues please refer to the MODIS/VIIRS Land Quality Assessment website.

The delivery of all Suomi National Polar-orbiting Partnership (Suomi NPP) VIIRS science data products will cease on November 2, 2026 (2026/306). Data users are encouraged to transition to the equivalent VJ209CMG (primary) or VJ109CMG (secondary) data products. The Visible Infrared Imaging Radiometer Suite (VIIRS) daily surface reflectance Climate Modeling Grid (VNP09CMG) Version 2 product provides an estimate of land surface reflectance from the NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) VIIRS sensor. Data are provided for three imagery bands (I1-I3) and nine moderate resolution bands (M1-M5, M7, M8, M10, M11) at 0.05 degree (~5,600 meter) resolution. The data are corrected for atmospheric conditions such as the effects of molecular gases, including ozone and water vapor, and for the effects of atmospheric aerosols. This product uses a weighted average of the best quality observation and is formatted as a CMG for use in climate simulation models. This product includes a total of 33 variables, including the twelve reflectance bands, five moderate resolution brightness temperature bands (M12-M16) and information layers representing relative azimuth angle, sensor zenith angle, solar zenith angle, reflectance band quality, time of day, and number mapping. Known Issues * For complete information about known issues please refer to the MODIS/VIIRS Land Quality Assessment website and in Section 4.0 of the User Guide.

The NOAA-20 Visible Infrared Imaging Radiometer Suite (VIIRS) Photosynthetically Active Radiation (PAR) gridded Level 3 product is produced at 1 kilometer pixel resolution at daily intervals. PAR is the incident solar radiation in the visible spectrum (400-700 nanometers) and is a significant variable in land surface models (LSMs), receiving increased attention due to its importance for the management and operation of solar energy systems. The VJ118 algorithm adapts the narrowband look-up table (LUT) approach to estimate PAR. The LUTs consider different types of loadings of aerosols and clouds at a variety of illumination/viewing geometry. The Algorithm Theoretical Basis Document (ATBD) is forthcoming and will provide additional details regarding the methodology used to create the data. Provided in the VJ118A2 product are variables for instantaneous total, direct, and diffuse PAR, as well as 3-hour PAR, daily mean PAR, and a quality variable.