Changes to ASTER Level 2 Product Generation Executables

Dec 15, 2021

On December 15, 2021, updates were implemented for ASTER Product Generation Executables (PGE) Version 3.4 to include changes to the ancillary data input options used in the atmospheric correction of ASTER Level 2 data products.

The updated PGE includes the following changes:

  • Aura Ozone Monitoring Instrument (OMI) has been added as one of the ancillary Column Ozone inputs for any observations made after May 27, 2020. The sequence of fallback options for ozone will remain the same.
  • Toolkit has been updated from Version 5.2.17 to 5.2.20. Users may notice minor differences between the two versions. Differences may include minuscule changes in digital numbers around the peripheral of the granule and boundaries of a cloud for Surface Reflectance (AST07) and Surface Radiance (AST09) Quality Assessment Data Plane depending on the Operating System and libraries being used by the user to process the data.

Additionally, the Naval Research Laboratory's (NRL) Climatology datasets, which are fallback inputs for the Ozone Column and the Moisture Profile, Temperature, and Atmospheric Pressure processing options will be removed from the Earthdata Order Form. It has been observed that PGEs generated with Climatology as an input yield noticeable differences statistically during image and spectral analysis. Climatology will continue to be used as the final default if neither of the first two selectable options are available for Ozone Column or Moisture Profile, Temperature, and Atmospheric Pressure. Users can check the OPERATIONALQUALITYFLAGEXPLANATION field in the metadata or the output file for atmospheric parameters that were applied.

The ancillary data input options are used in generating the following ASTER Level 2 on-demand products.

  • ASTER L2 Surface Emissivity (AST_05)
  • ASTER L2 Surface Reflectance VNIR and SWIR (AST_07)
  • ASTER L2 Surface Reflectance SWIR Crosstalk-Corrected (AST_07XT)
  • ASTER L2 Surface Kinetic Temperature (AST_08)
  • ASTER L2 Surface Radiance VNIR and SWIR (AST_09)
  • ASTER L2 Surface Radiance SWIR Crosstalk-Corrected (AST_09XT)
  • ASTER L2 Surface Radiance TIR (AST_09T)

ASTER Level 2 products can be ordered through NASA’s Earthdata Search.

Have questions? Please contact LP DAAC User Services.