Soft release of the v1.0 GEO-LEO Dark Target Aerosol product collections

This alert relates to a soft release of the Level-2 (L2) and Level-3 (L3) GEO-LEO Dark Target Aerosol collections whose temporal span ranges from January 2019 through December 2022.

The v1.0 GEO-LEO Dark Target Aerosol L2 collections were partially reprocessed since their original release in March 2024 to address a couple of issues. Since neither issue required reprocessing from the original Level-1B, these products are being re-released under their original version number (v1.0). They include the following updates:

1. Sensor and Solar Azimuth Angles' Fill-Value Modification: The fill-value for both the sensor azimuth angle and solar azimuth angle variables in the Level-2 (L2) product was modified. This modification includes two updates:
   • The FillValue was changed from -9999 to -19999.
   • Instances with actual missing information were replaced with the new FillValue. This change enables the plotting and/or analyzing of valid azimuth angles of -99.99 degrees, which otherwise runs the risk of being screened out by certain image processing systems.
2. Quality Assurance Filtering Correction: The Quality Assurance (QA)-filtered Science Data Set (SDS) named "Optical_Depth_Land_And_Ocean" was corrected, to include only over-land retrievals ("Corrected_Optical_Depth_Land") for which the QA flag value is greater than or equal to 2 (medium and high confidence), rather than QA greater than or equal to 1.
3. Data Provenance Enhancement: Given the fact that this reprocessed collection retains the same version 1.0 number, an additional global metadata attribute called "original_GranuleID" was added. It provides the original file name (or LocalGranuleID) with its processing date and time to facilitate data provenance trails for users who may have acquired products from the earlier collection. The new file's name, its processing date and time are provided in the LocalGranuleID attribute.
4. Correctly processed 191 datafiles: As part of the original release of the L2 GEO-LEO Dark Target Aerosol products in March 2024, 191 files (that include 15 files from ABI/G16, 4 files from ABI/G17, and 172 files from the Advanced Himawari Imager/H08) were not processed correctly that rendered them dysfunctional. All 191 files have been successfully reprocessed in this new release.

The updated landing pages for all these products will become available in a couple of weeks. This soft release is to facilitate users' access to these updated products ahead of the formal release. Users may directly download the Level-2 and the new Level-3 products from the following location:
    https://ladsweb.modaps.eosdis.nasa.gov/archive/allData/5021

The new Level-3 dataset is a merged, quarter-degree (QD) global aerosol dataset at 30-minute (half-hour or HH) intervals that is based on instrument observations from all GEO and LEO satellite platforms and instruments. Its short-name is XAERDT_L3_MEASURES_QD_HH.

If you have any questions, please contact our User Services.