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Description

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 layers for instantaneous total, direct, and diffuse PAR, as well as 3-hour PAR, daily mean PAR, and a quality layer.

Known Issues

• No Known Issues.

Improvements/Changes from Previous Versions

• N/A

Product Summary

Platforms
Suomi-NPP
Instruments
VIIRS
Spatial Extent
N: 90 S: -90 E: 180 W: -180
Spatial Resolution
1000 Meters x 1000 Meters
Geographic Region
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
GEODETIC
Temporal Extent
2012-01-19 to Present
Temporal Resolution
1 Day
Data Partner
Land Processes Distributed Active Archive Center (LP DAAC)
Land Science Investigator-led Processing System, Terrestrial Information Systems Laboratory, Earth Sciences Division, Sciences and Exploration Directorate, Goddard Space Flight Center, NASA (NASA/GSFC/SED/ESD/TISL/LandSIPS)
Concept ID
c2631841566-lpcloud
Data State
ACTIVE
Processing Level
3
Published
Updated

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.

Copy Citation

Wang, D. (2025). VIIRS/NPP Photosynthetically Active Radiation Daily L3 Global 1km SIN Grid V002 [Data set]. NASA Land Processes Distributed Active Archive Center. https://doi.org/10.5067/VIIRS/VNP18A2.002 Date Accessed: 2025-08-30

Data Center Citation

Dongdong Wang. 2025. VIIRS/NPP Photosynthetically Active Radiation Daily L3 Global 1km SIN Grid V002. Sioux Falls, South Dakota, USA: NASA Land Processes Distributed Active Archive Center. https://doi.org/10.5067/VIIRS/VNP18A2.002.

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