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STAR / SMCD / VIIRS Aerosol Calibration and Validation

VIIRS Aerosol Intermediate Product (IP)

The VIIRS aerosol Intermediate Product (IP) is the result of the aerosol retrieval performed on the 0.75-km pixels in a VIIRS granule of 768 x 3200 (along-track by cross-track) pixels using selected reflectances in the SDRs and ancillary data.

The IP retrievals produced by the VIIRS aerosol processing include AOT, APSP and aerosol model. They are recorded in two separate files. The names of these files start with IVAOT and IVAMI.

The file IVAOT contains

  • 550-nm aerosol optical thickness (faot550)
  • slant path 550-nm aerosol optical thickness (aotSlant550)
  • Angstrom exponent (angexp)
  • quality flags (QF1-QF5)

The IVAMI file is the Aerosol Model Information (AMI) file; it provides information on the aerosol model selected in the retrieval. The file contains

  • index of the model selected over land (amdl)
  • index of fine mode model selected over ocean (smmdl)
  • index of the coarse mode model selected over ocean (lgmdl)
  • percentage of the fine mode model in the mixture of fine and coarse mode models over ocean (combo)

The latitude and longitude coordinates of the pixels in the IVAOT and IVAMI files are given in the terrain-corrected geo-location file, GMTCO.

Detailed description of the contents of the above files are provided in the Common Data Format Control Book (CDFCB) linked from the Documentation page.

IP Data Access

The IP files can be access from NOAA CLASS.

To order the IVAOT and IVAMI files from CLASS:

  1. select JPSS Visible Infrared Imaging Radiometer Suite Intermediate Product (VIIRS_IPNG) Non-Gridded from the drop-down list at the top of the CLASS page;
  2. click GO;
  3. on the resulting page select VIIRS Aerosol Model Information (IVAMI) and/or VIIRS Aerosol Optical Thickness (IVAOT) from the Datatype under Advanced Search.

To obtain the corresponding geo-location file GMTCO,

  1. select JPSS Visible/Infrared Imaging Radiometer Suite Sensor Data Record (VIIRS_SDR) from the drop-down list on the CLASS home page;
  2. click GO;
  3. on the resulting page, under Advanced Search in the Geolocation data type section select VIIRS Moderate Bands SDR Terrain Corrected Geolocation (GMTCO).
  4. click Search or the Quick Search & Order button.
    • If you click Search you have an opportunity for reviewing the list of files before making an order. You can also further refine your selection on this page. Once done with selecting the files click the Goto Cart button to get to the Shopping Cart page.
    • If you click Quick Search & Order you are taken directly to the Shopping Cart page.
  5. click the Place Order button on the Shopping Cart page.
  6. Important: The GMTCO files available from CLASS have four granules aggregated into one file. Expand the list under Advanced Options and click the Yes radio button to request to de-aggregate the data. This will result in delivery of four individual files, one for each VIIRS granule.