MOD16A3 v006

MODIS/Terra Net Evapotranspiration Yearly L4 Global 500 m SIN Grid


PI: Steve Running

Terra MODIS Net Evapotranspiration Yearly L4 Global 500 m SIN Grid products are currently unavailable due to unexpected errors in the input data. Upon resolution of biases related to persistent cloud cover in the input Leaf Area Index/Fraction of Photosynthetically Active Radiation product, the MOD16A3 data will be reprocessed and made accessible from the LP DAAC. Users are encouraged to sign up for the LP DAAC listserv for future notifications on data availability.

Description

The MOD16A3 Version 6 Evapotranspiration/Latent Heat Flux product is a yearly composite dataset produced at 500 meter (m) pixel resolution. The algorithm is based on the logic of the Penman-Monteith equation, which includes inputs of daily meteorological reanalysis data along with Moderate Resolution Imaging Spectroradiometer (MODIS) remotely sensed data products such as vegetation property dynamics, albedo, and land cover.

Provided in the MOD16A3 product are layers for yearly Evapotranspiration (ET), Latent Heat Flux (LE), Potential ET (PET) and Potential LE (PLE) along with a quality control layer. Two low resolution browse images, ET and LE, are also available for each MOD16A3 granule.

The pixel values for the two Evapotranspiration layers (ET and PET) are the sum for all days within the defined year, and the pixel values for the two Latent Heat layers (LE and PLE) are the average of all days within the defined year.

Characteristics

Improvements/Changes from Previous Versions

  • Spatial resolution of Version 6 products has increased to nominal 500 m from nominal 1,000 m in Version 5.
  • Version 5 data products were previously distributed by the Numerical Terradynamic Simulation Group at the University of Montana. The Version 6 products are a continuation of this project.

Product Maturity

Validation at stage 1 has been achieved for MODIS Evapotranspiration products.

Collection and Granule

Collection

Characteristic Description
CollectionTerra MODIS
DOI10.5067/MODIS/MOD16A3.006
File Size~10 MB
Temporal ResolutionYearly
Temporal Extent2001-01-01 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) Layers5
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
ET_500m Total of Evapotranspiration kg/m²/year 16-bit unsigned integer 65529 to 65535 N/A 0 to 65500 0.1 N/A
LE_500m Average of Latent Heat Flux J/m²/day 16-bit signed integer 32761 to 32767 N/A 0 to 32700 10000 N/A
PET_500m Total Potential Evapotranspiration kg/m²/year 16-bit unsigned integer 65529 to 65535 N/A 0 to 65500 0.1 N/A
PLE_500m Average of Potential Latent Heat Flux J/m²/day 16-bit signed integer 32761 to 32767 N/A 0 to 32700 10000 N/A
ET_QC_500m Evapotranspiration Quality Assessment Percent 8-bit unsigned integer 255 N/A 0 to 100 N/A N/A

The header file of MOD16A3 lists only one fill value per layer, but there are a total of seven fill values to describe non-vegetated pixels.

ET_500m and PET_500m fill value classes

Value Description
65529 Land cover assigned as "unclassified" or not able to determine
65530 Land cover assigned as urban/built-up
65531 Land cover assigned as "permanent" wetlands/inundated marshland
65532 Land cover assigned as perennial snow, ice
65533 Land cover assigned as barren, sparse vegetation (rock, tundra, desert)
65534 Land cover assigned as perennial salt or water bodies
65535 Fill

LE_500m and PLE_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 vegetation (rock, tundra, desert)
32766 Land cover assigned as perennial salt or water bodies
32767 Fill

Product Quality

Quality for MOD16A3 is expressed as a percentage in the ET_QC_500m science dataset layer. More information on how this value is derived can be found in Section 6.2.2 of the User Guide.

Known Issues

Operational and uncertainty issues are provided under Section 3 in the User Guide.

Please refer to the MODIS Land Quality Assessment website for complete information about MOD16A3 known issues.

Documentation

Using the Data

Tools

Citation

DOI: 10.5067/MODIS/MOD16A3.006

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