Description
The NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) Land Surface Phenology data product provides global land surface phenology (GLSP) metrics at yearly intervals. The VNP22Q2 data product is derived from time series of the two-band Enhanced Vegetation Index-2 (EVI2) calculated from VIIRS Nadir Bidirectional Reflectance Distribution Function (BRDF)-Adjusted Reflectance (NBAR). Vegetation phenology metrics at 500 meter spatial resolution are identified for up to two detected growing cycles per year.
Provided in each VNP22Q2 product are 19 Science Dataset (SDS) layers. The product contains six phenological transition dates: onset of greenness increase, onset of greenness maximum, onset of greenness decrease, onset of greenness minimum, dates of mid-greenup, and senescence phases. The product also includes the growing season length. The greenness related metrics consist of EVI2 onset of greenness increase, EVI2 onset of greenness maximum, EVI2 growing season, rate of greenness increase and rate of greenness decrease. The confidence of phenology detection is provided as greenness agreement growing season, proportion of good quality (PGQ) growing season, PGQ onset greenness increase, PGQ onset greenness maximum, PGQ onset greenness decrease, and PGQ onset greenness minimum. The final layer is quality control specifying the overall quality of the product. A low-resolution browse image showing greenup is also available when viewing each VNP22Q2 granule.
Important information is provided in Section 5 of the User Guide when comparing VNP22Q2 with the MCD12Q2 data product.
Known Issues
- For complete information about known issues please refer to the MODIS/VIIRS Land Quality Assessment website.
Improvements/Changes from Previous Versions
- Improved calibration algorithm and better coefficients for entire Suomi NPP mission
- Improved geolocation accuracy and updates to fix outliers around maneuver periods and other events
- Corrections to the aerosol quantity flag (low, average, high) mainly over brighter surfaces in the mid to high latitudes such as desert and tropical vegetation areas. This has an impact on the retrieval of other downstream data products such as VNP13 Vegetation Indices and VNP43 BRDF/Albedo.
- Improved cloud mask input product for corrections along coastlines and artifacts from use of coarse resolution climatology data
- Replaced the land/water mask input product with MODIS heritage seven class land/water mask
- More details can be found in this VIIRS Land V2 Changes document.
Product Summary
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.
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Documents
ALGORITHM THEORETICAL BASIS DOCUMENT (ATBD) | The ATBD provides physical theory and mathematical procedures for the calculations used to produce the data products. | |
PRODUCT QUALITY ASSESSMENT | The LDOPE Land Product Quality Assessment website provides known issues, maneuvers, and product quality of the land products. | |
SCIENCE DATA PRODUCT VALIDATION | Validation at stage 1 has been achieved for the VIIRS land cover dynamic product suite. | |
SCIENCE DATA PRODUCT VALIDATION | Further details regarding VIIRS product validation and maturity status are available from VIIRS Land Product Quality Assessment site. | |
USER'S GUIDE | The technical information in the User's Guide enables users to interpret and use the data products. |