The VNP15A2H LAI/FPAR product over Lake Titicaca, Peru, August 30 - September 6, 2018.
View full-size imageThe 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 aboard the NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi 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. Visit VIIRS Land Product Quality Assessment Product Maturity for information on product maturity status.
| Characteristic | Description |
|---|---|
| Collection | Suomi NPP VIIRS |
| DOI | 10.5067/VIIRS/VNP15A2H.001 |
| File Size | ~4.4 MB |
| Temporal Resolution | Multi-Day |
| Temporal Extent | 2012-01-17 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 |
|---|---|---|---|---|---|---|---|
| Fpar | Fraction of Photosynthetically Active Radiation | N/A | 8-bit unsigned integer | 249 to 255 | N/A | 0 to 100 | 0.01 |
| FparExtra_QC | Pass-through Quality Control (QC) for FPAR | Class Flag | 8-bit unsigned integer | 255 | N/A | 0 to 254 | N/A |
| FparLai_QC | Quality for LAI and FPAR | Class Flag | 8-bit unsigned integer | 255 | N/A | 0 to 254 | N/A |
| FparStdDev | Standard deviation of FPAR | N/A | 8-bit unsigned integer | 248 to 255 | N/A | 0 to 100 | 0.01 |
| Lai | Leaf Area Index | m²/m² | 8-bit unsigned integer | 249 to 255 | N/A | 0 to 100 | 0.1 |
| LaiStdDev | Standard deviation for LAI | m²/m² | 8-bit unsigned integer | 248 to 255 | N/A | 0 to 100 | 0.1 |
| 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 and 5 of the User Guide.
The quality layer is stored in an efficient bit-encoded manner. The unpack_sds_bits executable from the LDOPE Tools is available to the user community to help parse and interpret the quality layer.
Quality assurance information should be considered when determining the usability of data for a particular science application. The ArcGIS MODIS-VIIRS Python Toolbox contains tools capable of decoding quality data layers while producing thematic quality raster files for each quality attribute.
In addition to data access and transformation processes, AppEEARS also has the capability to unpack and interpret the quality layers.
For complete information about product quality, refer to the VIIRS Land Product Quality Assessment website.
For complete information about known issues please refer to the MODIS/VIIRS Land Quality Assessment website.