VNP22Q2 v001

VIIRS/NPP Land Surface Phenology (Land Cover Dynamics) Yearly L3 Global 500 m SIN Grid


PI: Xiaoyang Zhang, Mark A. Friedl, and Geoffrey M. Henebry

Description

The Suomi National Polar-Orbiting Partnership (S-NPP) NASA Visible Infrared Imaging Radiometer Suite (VIIRS) Land Cover Dynamics 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 (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 Sections 5 of the User Guide when comparing VNP22Q2 with the MCD12Q2 data product.

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Characteristics

Product Maturity

Validation at stage 1 has been achieved for VIIRS land cover dynamic products.

Collection and Granule

Collection

Characteristic Description
CollectionS-NPP VIIRS
DOI10.5067/VIIRS/VNP22Q2.001
File Size~659.52 MB
Temporal ResolutionYearly
Temporal Extent2013-01-01 to 2018-12-31
Spatial ExtentGlobal
Coordinate SystemSinusoidal
DatumN/A
File FormatHDF-EOS5
Geographic DimensionsGlobal

Granule

Characteristic Description
Number of Science Dataset (SDS) Layers19
Columns/Rows2400 x 2400
Pixel Size500 m

Layers

SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
Date_Mid_Greenup_Phase¹ Date at a mid-greenup phase Day 16-bit unsigned integer 32767 N/A 1 to 32766 N/A
Date_Mid_Senescence_Phase¹ Date at a mid-senescence phase Day 16-bit unsigned integer 32767 N/A 1 to 32766 N/A
EVI2_Growing_Season_Area Integrated EVI2 during a growing season EVI2 16-bit unsigned integer 32767 N/A 1 to 32766 0.01
EVI2_Onset_Greenness_Increase EVI2 value at greenup onset EVI2 16-bit unsigned integer 32767 N/A 1 to 10000 0.0001
EVI2_Onset_Greenness_Maximum EVI2 value at maturity onset EVI2 16-bit unsigned integer 32767 N/A 1 to 10000 0.0001
GLSP_QC Global Land Surface Phenology Quality Control N/A 8-bit unsigned integer 255 N/A 1 to 100 N/A
Greenness_Agreement_Growing_Season EVI2 agreement between modeled values and raw observations N/A 8-bit unsigned integer 255 N/A 1 to 100 N/A
Growing_Season_Length Growing Season Length Number 16-bit unsigned integer 32767 N/A 1 to 366 N/A
Onset_Greenness_Decrease¹ Date at which canopy greenness begins to decrease Day 16-bit unsigned integer 32767 N/A 1 to 32766 N/A
Onset_Greenness_Increase¹ Date of onset of greenness increase Day 16-bit unsigned integer 32767 N/A 1 to 32766 N/A
Onset_Greenness_Maximum¹ Date at which canopy greenness approaches its seasonal maximum Day 16-bit unsigned integer 32766 N/A 1 to 32766 N/A
Onset_Greenness_Minimum¹ Date at which canopy greenness reaches a minimum Day 16-bit unsigned integer 32766 N/A 1 to 32766 N/A
PGQ_Growing_Season Proportion of good quality of VIIRS observations during a vegetation growing season N/A 8-bit unsigned integer 255 N/A 1 to 100 N/A
PGQ_Onset_Greenness_Decrease Proportion of good quality around senescence onset N/A 8-bit unsigned integer 255 N/A 1 to 100 N/A
PGQ_Onset_Greenness_Increase Proportion of good quality around greenup onset N/A 8-bit unsigned integer 255 N/A 1 to 100 N/A
PGQ_Onset_Greenness_Maximum Proportion of good quality around maturity onset N/A 8-bit unsigned integer 255 N/A 1 to 100 N/A
PGQ_Onset_Greenness_Minimum Proportion of good quality around dormancy onset N/A 8-bit unsigned integer 255 N/A 1 to 100 N/A
Rate_Greenness_Decrease Rates of change in EVI2 values during a senescence phase EVI2/Day 16-bit unsigned integer 32767 N/A 1 to 32766 0.0001
Rate_Greenness_Increase Rates of change in EVI2 values during a greenup phase EVI2/Day 16-bit unsigned integer 32767 N/A 1 to 32766 0.0001

¹Please use the following calculation for the Scale Factor = File data – (given year-2000)*366

Product Quality

Detailed information on quality for the VNP22 products can be found in Section 2 of the User Guide.
For additional information on product quality, refer to the VIIRS Land Product Quality website.

Known Issues

No known issues.

Documentation

Using the Data

Access Data

Citation

DOI: 10.5067/VIIRS/VNP22Q2.001

About the Image

VNP22Q2 500 m Greenup Onset image for North America, 2014.

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