The Visible Infrared Imaging Radiometer Suite (VIIRS) Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) Version 1 data product provides information about the vegetative canopy layer at 500 meter resolution (VNP15A2H). The VIIRS sensor is located onboard the NOAA/NASA joint Suomi National Polar-Orbiting Partnership (S-NPP) satellite. LAI is an index that quantifies the one-sided leaf area of a canopy, while FPAR is the fraction of incoming solar energy absorbed through photosynthesis at 400 to 700 nanometers. This product is intentionally designed after the Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) LAI/FPAR operational algorithm to promote the continuity of the Earth Observation System (EOS) mission.
The VNP15A2H product includes six Science Data Set Layers for the analysis of key factors in LAI/FPAR measurements. These include the LAI and FPAR measurements, quality detail for LAI/FPAR, extra quality detail for FPAR, and the standard deviation for LAI and FPAR. Two low resolution browse images are also available for each VNP15A2H granule: LAI and FPAR.
Validation at stage 1 has been achieved for the VIIRS LAI/FPAR products.
| Characteristic | Description |
|---|---|
| Collection | S-NPP VIIRS |
| DOI | 10.5067/VIIRS/VNP15A2H.001 |
| File Size | ~35 MB |
| Temporal Resolution | Multi-Day |
| Temporal Extent | 2012-01-19 to Present |
| Spatial Extent | Global |
| Coordinate System | Sinusoidal |
| Datum | N/A |
| File Format | HDF-EOS5 |
| Geographic Dimensions | 1200 km x 1200 km |
| Characteristic | Description |
|---|---|
| Number of Science Dataset (SDS) Layers | 6 |
| Columns/Rows | 2400 x 2400 |
| Pixel Size | 500 m |
| SDS Name | Description | Units | Data Type | Fill Value | No Data Value | Valid Range | Scale Factor | Additional Offset |
|---|---|---|---|---|---|---|---|---|
| Fpar | Fraction of Photosynthetically Active Radiation | N/A | 8-bit unsigned integer | 249 to 255 | N/A | 0 to 100 | 0.01 | N/A |
| FparExtra_QC | Pass-through Quality Control (QC) for FPAR | Class Flag | 8-bit unsigned integer | 255 | N/A | 0 to 254 | N/A | N/A |
| FparLai_QC | Quality for LAI and FPAR | Class Flag | 8-bit unsigned integer | 255 | N/A | 0 to 254 | N/A | N/A |
| FparStdDev | Standard deviation of FPAR | N/A | 8-bit unsigned integer | 248 to 255 | N/A | 0 to 100 | 0.01 | N/A |
| Lai | Leaf Area Index | m²/m² | 8-bit unsigned integer | 249 to 255 | N/A | 0 to 100 | 0.1 | N/A |
| LaiStdDev | Standard deviation for LAI | m²/m² | 8-bit unsigned integer | 248 to 255 | N/A | 0 to 100 | 0.1 | N/A |
| Value | Description |
|---|---|
| 249 | land cover assigned as “unclassified” or not able to determine |
| 250 | land cover assigned as urban/built−up |
| 251 | land cover assigned as “permanent” wetlands/inundated marshlands |
| 252 | land cover assigned as perennial snow, ice |
| 253 | land cover assigned as barren, sparse vegetation (rock, tundra, desert) |
| 254 | land cover assigned as perennial salt or inland fresh water |
| 255 | Fillvalue, assigned when: the VNP09GA surface reflectance for channels VIS, NIR was assigned as Fillvalue, or land cover pixel itself was assigned Fillvalue of 255 or 254 |
| Value | Description |
|---|---|
| 248 | No standard deviation available, pixel produced using backup method |
| 249 | land cover assigned as “unclassified” or not able to determine |
| 250 | land cover assigned as urban/built−up |
| 251 | land cover assigned as “permanent” wetlands/inundated marshlands |
| 252 | land cover assigned as perennial snow, ice |
| 253 | land cover assigned as barren, sparse vegetation (rock, tundra, desert) |
| 254 | land cover assigned as perennial salt or inland fresh water |
| 255 | Fillvalue, assigned when: the VNP09GA surface reflectance for channels VIS, NIR was assigned as Fillvalue, or land cover pixel itself was assigned Fillvalue of 255 or 254 |
The bit field mappings for QC layers are provided in Sections 4.2 Tables 4-5 of the User Guide.
For complete information about product quality, refer to the VIIRS Land Product Quality Assessment website.