The Land Processes Distributed Active Archive Center (LP DAAC) has released Visible Infrared Imaging Radiometer Suite (VIIRS) Version 2 Evapotranspiration, Gross Primary Productivity (GPP), and Net Primary Production (NPP) Data Products from the NOAA-21 satellite. Included in these products are variables for evapotranspiration, latent heat flux, gross primary productivity, net photosynthesis, and net primary production.
Users are encouraged to use the gap-filled (GF) products which are generated only at the end of a given year. Forward processing is available for VJ216A2 and VJ217A2 to accommodate users who need more recent data.
Learn more about the VIIRS Evapotranspiration, Gross Primary Productivity and Net Photosynthesis data products by clicking the links in the Referenced Datasets section below. The links also provide the Digital Object Identifier for the dataset, along with several suggested styles for properly citing the data.
Explore and access these data products using NASA’s Earthdata Search. Please contact Earthdata User Services with any questions.
https://www.earthdata.nasa.gov/data/alerts-outages/noaa-21-viirs-version-2-evapotranspiration-gpp-npp-data-products-released
NOAA-21 VIIRS Version 2 Evapotranspiration, GPP, and NPP Data Products Released
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Re: NOAA-21 VIIRS Version 2 Evapotranspiration, GPP, and NPP Data Products Released
Please note the following knowing know issue related to the VIIRS 16s products: https://landweb.modaps.eosdis.nasa.gov/displayissue?id=1480
Work is on-going to release the Versions 2.1 dataset. The LP DAAC will post an announcement once the 2.1 data are available.
Data users are advised that the Collection 2 (C2) VIIRS Evapotranspiration (ET) and Potential Evapotranspiration (PET) 8-day and annual data products-derived from Suomi-NPP (VNP16A2GF/A3GF), JPSS-I (VJ116A2GF/A3GF), and JPSS-2 (VJ216A2GF/A3GF) contain known issues. To ensure the highest data quality for ET/PET estimates, users should transition to the reprocessed Collection 2.1 (C2.1) data products.
The anomalies in the C2 data stem from two issues within the ET/PET Product Generation Executables (PGEs):
Wet Canopy Fraction Calculation: During a biophysiological parameter update, the equation used to estimate the fraction of wet canopy was inadvertently modified. Consequently, the fraction of wet canopy is underestimated when the relative humidity exceeds 70%. This perceived reduction in available water leads to an underestimation of ET, particularly in humid ecosystems.
PGE Memory Leak:Updates to the 8-day composite processing introduced a memory leak, resulting in inconsistent processing behavior. As a result, certain 10-degree Sinusoidal map projection tiles generated 8-day composites utilizing fewer than the full 8 days of data.
The C2.1 VIIRS ET/PET reprocessing corrects both of these issues by restoring the proper wet canopy equation and resolving the memory leak. The C2.1 products are confirmed to be free of these anomalies. To ensure the correct files are being used, product versions can be verified via their HDF5 filenames: legacy C2 utilizes the string ".002.", while the updated C2.1 uses ".021.".
Further technical details regarding the C2 data are documented on the LDOPE website at: C2 VIIRS ET PET Issues Technical Document (https://landweb.modaps.eosdis.nasa.gov/data/filePost/C2_VIIRS_ET_PET_Issues_TechnicalDocument.pdf)
Work is on-going to release the Versions 2.1 dataset. The LP DAAC will post an announcement once the 2.1 data are available.
Data users are advised that the Collection 2 (C2) VIIRS Evapotranspiration (ET) and Potential Evapotranspiration (PET) 8-day and annual data products-derived from Suomi-NPP (VNP16A2GF/A3GF), JPSS-I (VJ116A2GF/A3GF), and JPSS-2 (VJ216A2GF/A3GF) contain known issues. To ensure the highest data quality for ET/PET estimates, users should transition to the reprocessed Collection 2.1 (C2.1) data products.
The anomalies in the C2 data stem from two issues within the ET/PET Product Generation Executables (PGEs):
Wet Canopy Fraction Calculation: During a biophysiological parameter update, the equation used to estimate the fraction of wet canopy was inadvertently modified. Consequently, the fraction of wet canopy is underestimated when the relative humidity exceeds 70%. This perceived reduction in available water leads to an underestimation of ET, particularly in humid ecosystems.
PGE Memory Leak:Updates to the 8-day composite processing introduced a memory leak, resulting in inconsistent processing behavior. As a result, certain 10-degree Sinusoidal map projection tiles generated 8-day composites utilizing fewer than the full 8 days of data.
The C2.1 VIIRS ET/PET reprocessing corrects both of these issues by restoring the proper wet canopy equation and resolving the memory leak. The C2.1 products are confirmed to be free of these anomalies. To ensure the correct files are being used, product versions can be verified via their HDF5 filenames: legacy C2 utilizes the string ".002.", while the updated C2.1 uses ".021.".
Further technical details regarding the C2 data are documented on the LDOPE website at: C2 VIIRS ET PET Issues Technical Document (https://landweb.modaps.eosdis.nasa.gov/data/filePost/C2_VIIRS_ET_PET_Issues_TechnicalDocument.pdf)
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