Recent advances on a multi-sensor NASA Program of Record dataset (CLDPROP) for cloud properties from MODIS, VIIRS, and beyond

The NASA CLDPROP cloud-top and optical properties products were designed to bridge the early afternoon data records of MODIS on NASA’s Aqua satellite and VIIRS on the current generation of advanced NOAA operational weather satellites, with the goal of creating a multi-sensor, multi-decadal continuous climate data record for clouds that addresses the specific needs of NASA’s R&A program. The CLDPROP cloud products follow a “continuity of approach” paradigm – applying common cloud-top and optical properties algorithms to a subset of channels available on both MODIS and VIIRS, thus mitigating to the extent possible the impacts of differing spectral information content, science algorithm approaches, and ancillary input dataset usage. As the decommissioning of NASA’s venerable Earth Observing System (EOS) missions, including Aqua and its morning afternoon sibling Terra, draws closer, sustaining continuity algorithm efforts into the VIIRS era and beyond is an essential enabling activity for climate studies and trend monitoring.

Here, we provide details on the Version 2 (V2) updates for CLDPROP, which is expected to be in reprocessing/forward processing for Aqua MODIS, SNPP VIIRS, and NOAA-20/21 VIIRS at the time of this presentation. The V2 products for each of these platforms/sensors, like their V1/V1.1 predecessors, will be publicly archived and distributed by the LAADS DAAC at NASA Goddard Space Flight Center. Updates for V2 include pixel-level SW and LW broadband TOA and surface flux calculations enabling radiative studies consistent with the cloud-top/optical property retrievals; a research-level IR cloud-top properties algorithm that also provides day/night retrievals of ice cloud optical properties; a new cloud thermodynamic phase classification algorithm leveraging machine learning; and a new, parallel CLDMSK (cloud mask) and CLDPROP product line leveraging co-located IR sounder observations (VIIRS+CrIS, MODIS+AIRS) to mitigate the lack of IR absorbing channels on VIIRS that have enhanced information content for high, thin clouds. Furthermore, assessments of the inter-sensor relative radiometric calibration of the key shortwave channels used for cloud optical property retrievals are ongoing, including exploration of new approaches given the orbital drift of Aqua.