MODIS/Aqua Net Primary Production Gap-Filled Yearly L4 Global 500m SIN Grid V061

The 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](https://doi.org/10.5067/MODIS/MYD17A2H.061)) 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](https://doi.org/10.5067/modis/myd15a2h.061) 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.

Known Issues
* 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](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=MODIS&sat=Aqua&as=61).