MOD17A3HGF v061

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

PI: Steve Running


The MOD17A3HGF Version 6.1 product provides information about annual Gross and Net Primary Production (GPP and NPP) at 500 meter (m) pixel resolution. Annual Terra Moderate Resolution Imaging Spectroradiometer (MODIS) GPP and NPP is derived from the sum of all 8-day GPP Net Photosynthesis (PSN) products (MOD17A2H) from the given year. The PSN value is the difference of the GPP and the Maintenance Respiration (MR).

The MOD17A3HGF will be generated at the end of each year when the entire yearly 8-day MOD15A2H is available. Hence, the gap-filled MOD17A3HGF is the improved MOD17, which has cleaned the poor-quality inputs from 8-day Leaf Area Index and Fraction of Photosynthetically Active Radiation (LAI/FPAR) 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 MOD17A3HGF in near-real time because it will be generated only at the end of a given year.

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Improvements/Changes from Previous Versions

  • The Version 6.1 Level-1B (L1B) products have been improved by undergoing various calibration changes that include: changes to the response-versus-scan angle (RVS) approach that affects reflectance bands for Aqua and Terra MODIS, corrections to adjust for the optical crosstalk in Terra MODIS infrared (IR) bands, and corrections to the Terra MODIS forward look-up table (LUT) update for the period 2012 - 2017.
  • A polarization correction has been applied to the L1B Reflective Solar Bands (RSB).
  • The product uses Climatology LAI/FPAR as back up to the operational LAI/FPAR.

Product Maturity

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 MOD17 data products are available from the MODIS Land Team Validation site.

Collection and Granule


Characteristic Description
CollectionTerra MODIS
File Size~10 MB
Temporal ResolutionYearly
Temporal Extent2001-01-01 to Present
Spatial ExtentGlobal
Coordinate SystemSinusoidal
File FormatHDF-EOS
Geographic Dimensions1200 km x 1200 km


Characteristic Description
Number of Science Dataset (SDS) Layers3
Columns/Rows2400 x 2400
Pixel Size500 m

Layers / Variables

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 Bits Percent 8-bit unsigned integer 249 to 255 N/A 0 to 100 N/A

Gpp_500m Fill Value Classes

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

Npp_500m Fill Value Classes

Value Description
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

Npp_QC_500m Fill Value Classes

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

Product Quality

Quality for MOD17A3HGF 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.

Additional information on the Collection 5.5 improved 1 km MOD17 product by the Numerical Terradynamic Simulation Group (NTSC) at the University of Montana and a comparison with the MOD17HGF products are provided in MOD17HGF_vs_NTSG.pdf.

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.

About the image

Terra MODIS net primary productivity (NPP) data from the MOD17A3HGF product over Chile and Argentina, 2006.

View full-size image


User Guide
Algorithm Theoretical Basis Document (ATBD)
File Specification

Using the Data

Access Data


DOI: 10.5067/MODIS/MOD17A3HGF.061