Aqua MODIS net primary productivity (NPP) data from the MYD17A3HGF product over Venezuela, 2020.
View full-size imageThe MYD17A3HGF Version 6.1 product provides information about annual Gross and Net Primary Production (GPP and NPP) at 500 meter (m) pixel resolution. Annual Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) GPP and NPP is derived from the sum of all 8-day GPP and Net Photosynthesis (PSN) products (MYD17A2H) from the given year. The PSN value is the difference of the GPP and the Maintenance Respiration (MR).
The MYD17A3HGF will be generated at the end of each year when the entire yearly 8-day MYD15A2H is available. Hence, the gap-filled MYD17A3HGF is the improved MYD17, which has cleaned the poor-quality inputs from 8-day Leaf Area Index and Fraction of Photosynthetically Active Radiation (FPAR/LAI) based on the Quality Control (QC) label for every pixel. If any LAI/FPAR pixel did not meet the quality screening criteria, its value is determined through linear interpolation. However, users cannot get MYD17A3HGF in near-real time because it will be generated only at the end of a given year.
Validation at stage 3 has been achieved for the MODIS Gross and Net Primary Productivity data products. Further details regarding MODIS land product validation for the MYD17 data products are available from the MODIS Land Team Validation site.
| Characteristic | Description |
|---|---|
| Collection | Aqua MODIS |
| DOI | 10.5067/MODIS/MYD17A3HGF.061 |
| File Size | ~0.8 MB |
| Temporal Resolution | Yearly |
| Temporal Extent | 2002-07-04 to Present |
| Spatial Extent | Global |
| Coordinate System | Sinusoidal |
| Datum | N/A |
| File Format | HDF-EOS |
| Geographic Dimensions | 1200 km x 1200 km |
| Characteristic | Description |
|---|---|
| Number of Science Dataset (SDS) Layers | 3 |
| Columns/Rows | 2400 x 2400 |
| Pixel Size | 500 m |
| SDS Name | Description | Units | Data Type | Fill Value | No Data Value | Valid Range | Scale Factor |
|---|---|---|---|---|---|---|---|
| Gpp_500m | Gross Primary Productivity | kgC/m²/year | 16-bit unsigned integer | 65529 to 65535 | N/A | 0 to 65500 | 0.0001 |
| Npp_500m | Net Primary Productivity | kgC/m²/year | 16-bit signed integer | 32761 to 32767 | N/A | -30000 to 32700 | 0.0001 |
| Npp_QC_500m | Quality Control | Percent | 8-bit unsigned integer | 249 to 255 | N/A | 0 to 100 | N/A |
| Value | Description |
|---|---|
| 65529 | Land cover assigned as unclassified |
| 65530 | Land cover assigned as urban/built-up |
| 65531 | Land cover assigned as permanent wetlands/marshes |
| 65532 | Land cover assigned as perennial snow, ice on pixel |
| 65533 | Land cover assigned as barren, very sparsely vegetated |
| 65534 | Land cover assigned as water (ocean or inland) |
| 65535 | Fill Value: not-computed or outside projection |
| Value | Classes |
|---|---|
| 32761 | Land cover assigned as "unclassified" or not able to determine |
| 32762 | Land cover assigned as urban/built-up |
| 32763 | Land cover assigned as "permanent" wetlands/inundated marshland |
| 32764 | Land cover assigned as perennial snow, ice |
| 32765 | Land cover assigned as barren, sparse veg (rock, tundra, desert) |
| 32766 | Land cover assigned as perennial salt or inland fresh water |
| 32767 | Fill Value |
| 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 marshland |
| 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 water bodies |
| 255 | Fill |
Quality for MYD17A3HGF is expressed as a percentage in the Npp_QC_500m science dataset layer. More information on how this value is derived can be found in Section 4.2 of the User Guide.
Operational and uncertainty issues are provided under Section 2 in the User Guide.
For complete information about known issues please refer to the MODIS/VIIRS Land Quality Assessment website.