MYD16A2 v061

MODIS/Aqua Net Evapotranspiration 8-Day L4 Global 500 m SIN Grid


PI: Steve Running

Description

The Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) MYD16A2 Version 6.1 Evapotranspiration/Latent Heat Flux product is an 8-day composite dataset produced at 500 meter (m) pixel resolution. The improved algorithm is based on the logic of the Penman-Monteith equation, which includes inputs of daily meteorological reanalysis data along with MODIS remotely sensed data products such as vegetation property dynamics, albedo, and land cover.

Provided in the MYD16A2 product are layers for composited 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 MYD16A2 granule.

The pixel values for the two Evapotranspiration layers (ET and PET) are the sum of all eight days within the composite period, and the pixel values for the two Latent Heat layers (LE and PLE) are the average of all eight days within the composite period. Note that the last acquisition period of each year is a 5 or 6-day composite period depending on the year.

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Characteristics

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 Evapotranspiration data products. Further details regarding MODIS land product validation for the MYD16 data products are available from the MODIS Land Team Validation site.

Collection and Granule

Collection

Characteristic Description
CollectionAqua MODIS
DOI10.5067/MODIS/MYD16A2.061
File Size~25 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) Layers5
Columns/Rows2400 x 2400
Pixel Size500 m

Layers

SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
ET_500m Total Evapotranspiration kg/m²/8day 16-bit signed integer 32761 to 32767 N/A -32767 to 32700 0.1
LE_500m Average Latent Heat Flux J/m²/day 16-bit signed integer 32761 to 32767 N/A -32767 to 32700 10000
PET_500m Total Potential Evapotranspiration kg/m²/8day 16-bit signed integer 32761 to 32767 N/A -32767 to 32700 0.1
PLE_500m Average Potential Latent Heat Flux J/m²/day 16-bit signed integer 32761 to 32767 N/A -32767 to 32700 10000
ET_QC_500m Evapotranspiration Quality Control flags Bit Field 8-bit unsigned integer 255 N/A 0 to 254 N/A

Product Quality

The pixel level quality control layer (ET_QC_500m) is a copy of the quality control data layer of the corresponding input LAI/FPAR (MYD15A2H) granule of the same 8-day composite period and does not reflect the quality of the retrieved evapotranspiration. The current operational process does not generate pixel level science quality information. Users are advised to exercise caution while using the product in their application.

Additional information related to the cloud/aerosol screening and quality for input products are provided in Section 3.2.1 in the User Guide. Mappings for the ET QC layer and an explanation on how to interpret this information are provided under Section 6.2.1 in the User Guide.

Known Issues

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

For complete information about known issues please refer to the MODIS/VIIRS Land Quality Assessment website.

Documentation

User Guide
Algorithm Theoretical Basis Document (ATBD)
File Specification

Using the Data

Access Data

Citation

DOI: 10.5067/MODIS/MYD16A2.061

About the Image

Aqua MODIS evapotranspiration (ET) data from the MYD16A2 product over east Africa from January 1 - 8, 2021.

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