MODIS-VIIRS Dark Target Aerosol Retrieval as a Climate Data Record

A Dark Target aerosol product for VIIRS is approaching operational status after testing with retrievals in Intermediate File Format, which simplified the algorithm for a “lowest common denominator” comparison to aerosol optical depths retrieved by Aqua-MODIS. The final product is updated to use the MODIS-VIIRS Cloud Mask and a consistent format with other VIIRS data products produced through University of Wisconsin-Madison SIPS. In addition, we are considering calibration adjustments that would correct for the instrument differences found between MODIS and VIIRS during testing. At the same time, enhancements to the MODIS version of the retrieval included in the upcoming Collection 6.1 are likely to be incorporated into the VIIRS algorithm as well, and testing is underway to port the Dark Target algorithm to Himawari-8. While the VIIRS Dark Target retrievals are made independently of MODIS and have an updated dataset list, it is crucial to have data continuity across the transition from one instrument to the next. The MODIS data record begins in 1999, but for climate studies examining trends in air quality and radiative forcing due to aerosols, the data record must extend beyond the lifespan of any individual instrument. With Suomi-NPP launched in 2012 and more VIIRS launches to come, continuity between MODIS and VIIRS ensures that a multidecadal record can be assembled.