MYD17A2H v006

MODIS/Aqua Gross Primary Productivity 8-Day L4 Global 500 m SIN Grid


PI: Steve Running

Description

The MYD17A2H Version 6 Gross Primary Productivity (GPP) product is a cumulative 8-day composite of values with 500 meter (m) pixel size based on the radiation use efficiency concept that can be potentially used as inputs to data models to calculate terrestrial energy, carbon, water cycle processes, and biogeochemistry of vegetation. The data product includes information about GPP and Net Photosynthesis (PSN). The PSN band values are the GPP minus the Maintenance Respiration (MR). The data product also contains a PSN Quality Control (QC) layer. The quality layer contains quality information for both the GPP and the PSN.

Characteristics

Improvements/Changes from Previous Versions

  • The product uses updated Biome Property Look-Up Tables (BPLUT) and an updated version of the daily Global Modeling and Assimilation Office (GMAO) meteorological data.
  • The products are now generated at the native resolution of 500 m using the Moderate Resolution Imaging Spectroradiometer (MODIS) Leaf Area Index (LAI)/Fraction of Photosynthetically Active Radiation (FPAR) (MYD15A2H) 8-day composite at 500 m resolution.

Product Maturity

Stage 3 validation has been achieved for MYD17 products.

Collection and Granule

Collection

Characteristic Description
CollectionTerra MODIS
DOI10.5067/MODIS/MYD17A2H.006
File Size~3 MB
Temporal ResolutionMulti-Day
Temporal Extent2002-07-04 to Present
Spatial ExtentGlobal
Coordinate SystemSinusoidal
DatumN/A
File FormatHDF-EOS
Geographic Dimensions1200 km x 1200 km

Granule

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

Layers

SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor Additional Offset
Gpp_500m Gross Primary Productivity kg C/m² 16-bit signed integer 32761 to 32767 N/A 0 to 30000 0.0001 N/A
PsnNet_500m Net Photosynthesis kg C/m² 16-bit signed integer 32761 to 32767 N/A -30000 to 30000 0.0001 N/A
Psn_QC_500m Quality Control Indicators N/A 8-bit unsigned integer 255 N/A 0 to 254 N/A N/A

Non-Terrestrial 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|

Product Quality

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 this layer.

In addition to data access and transformation processes, AppEEARS also has the capability to unpack and interpret the quality layer.

The bit flags for the Psn_QC_500m Quality layer are provided in the MYD17A2H File Specification.

Known Issues

For complete information about the MYD17A2H known issues refer to the MODIS Land Quality Assessment website.

Documentation

Using the Data

Tools

Citation

DOI: 10.5067/MODIS/MYD17A2H.006

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