Release of Version 3.4 ASTER Level 2 Order Processing

October 23, 2019
By: LP DAAC

The LP DAAC is pleased to announce the release of Science Scalable Scripts-based Science for Missions (S4PM) Version 3.4 for generating ASTER Level 2 on-demand products. The release of the S4PM processing system includes the following:

  • A new option has been added to use MODIS version 6.1 (MOD07_L2) Temperature, Water Vapor, and Pressure inputs. The default order option will remain as NCEP.
  • The default for the Ozone input data has been switched from TOVS to the new TOAST/EPTOMS option.
  • The Level 2 algorithm has been updated to provide a fall back option for the Temperature/Water Vapor/Pressure and Ozone input selections. Both selections will automatically revert to the next lower input if the selected input is not available.
    • The Temperature/Water Vapor/Pressure input will fall back from MOD07 > GDAS/NCEP > Climatology
    • The Ozone input will fall back from TOAST/EPTOMS > OZ_DLY/TOVS > Climatology
  • Users can check the metadata files of their output product files to see if a fall back has occurred and identify which input source was used to generate their Level 2 product files.
    • The OPERATIONALQUALITYFLAGEXPLANATION field in the metadata file will indicate if a fall back has occurred and which value was used.

The metadata information regarding if a fall back occurred is only available for the AST_07, AST_07XT, AST_09, AST_09XT and AST_09T products at this time but will be added to the AST_05 and AST_08 products in a future release. Below is a list of ASTER Level 2 products that are available for on-demand processing:

  • 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)

The added input data options will provide users with better input data coverage (simultaneously acquired MODIS data vs. 6-hourly modeled NCEP input data) and consequently more accurate Level 2 output data.

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

Have questions? Contact LP DAAC User Services at lpdaac@usgs.gov.