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.
Version Description
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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File Naming Convention
The file name begins with the Product Short Name (VNP22Q2) followed by the Julian Date of Acquisition formatted as AYYYYDDD (A2023001), the Tile Identifier which is horizontal tile and vertical tile provided as hXXvYY (h23v08), the Version of the data collection (002), the Julian Date and Time of Production designated as YYYYDDDHHMMSS (2024234130237), and the Data Format (h5).
Documents
USER'S GUIDE
ALGORITHM THEORETICAL BASIS DOCUMENT (ATBD)
PRODUCT QUALITY ASSESSMENT
Publications Citing This Dataset
Variables
Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.
The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.
Name Sort descending | Description | Units | Data Type | Fill Value | Valid Range | Scale Factor |
---|---|---|---|---|---|---|
Date_Mid_Greenup_Phase | Date at a mid-greenup phase | Day | uint16 | 32767 | 32767 to 32766 | N/A |
Date_Mid_Senescence_Phase | Date at a mid-senescence phase | Day | uint16 | 32767 | 32767 to 32766 | N/A |
EVI2_Growing_Season_Area | Integrated EVI2 during a growing season | EVI2 | uint16 | 32767 | 32767 to 32766 | 0.01 |
EVI2_Onset_Greenness_Increase | EVI2 value at greenup onset | EVI2 | uint16 | 32767 | 32767 to 10000 | 0.0001 |
EVI2_Onset_Greenness_Maximum | EVI2 value at maturity onset | EVI2 | uint16 | 32767 | 32767 to 10000 | 0.0001 |
GLSP_QC | Global Land Surface Phenology Quality Control | N/A | uint8 | 255 | 255 to 100 | N/A |
Greenness_Agreement_Growing_Season | EVI2 agreement between modeled values and raw observations | N/A | uint8 | 255 | 255 to 100 | N/A |
Growing_Season_Length | Growing Season Length | Number | uint16 | 32767 | 32767 to 366 | N/A |
Onset_Greenness_Decrease | Date at which canopy greenness begins to decrease | Day | uint16 | 32767 | 32767 to 32766 | N/A |
Onset_Greenness_Increase | Date of onset of greenness increase | Day | uint16 | 32767 | 32767 to 32766 | N/A |
Onset_Greenness_Maximum | Date at which canopy greenness approaches its seasonal maximum | Day | uint16 | 32766 | 32766 to 32766 | N/A |
Onset_Greenness_Minimum | Date at which canopy greenness reaches a minimum | Day | uint16 | 32766 | 32766 to 32766 | N/A |
PGQ_Growing_Season | Proportion of good quality of VIIRS observations during a vegetation growing season | N/A | uint8 | 255 | 255 to 100 | N/A |
PGQ_Onset_Greenness_Decrease | Proportion of good quality around senescence onset | N/A | uint8 | 255 | 255 to 100 | N/A |
PGQ_Onset_Greenness_Increase | Proportion of good quality around greenup onset | N/A | uint8 | 255 | 255 to 100 | N/A |
PGQ_Onset_Greenness_Maximum | Proportion of good quality around maturity onset | N/A | uint8 | 255 | 255 to 100 | N/A |
PGQ_Onset_Greenness_Minimum | Proportion of good quality around dormancy onset | N/A | uint8 | 255 | 255 to 100 | N/A |
Rate_Greenness_Decrease | Rates of change in EVI2 values during a senescence phase | EVI2/Day | uint16 | 32767 | 32767 to 32766 | 0.0001 |
Rate_Greenness_Increase | Rates of change in EVI2 values during a greenup phase | EVI2/Day | uint16 | 32767 | 32767 to 32766 | 0.0001 |