Evaluating the NASA Aqua MODIS/SNPP VIIRS CLDPROP continuity cloud products

Abstract:

Version 1.1 of the NASA Aqua MODIS/SNPP VIIRS CLDPROP continuity cloud products was released to the public in November 2019. These cloud products, having heritage with the NASA MODIS MOD06 cloud optical properties product and the NOAA GOES-R Algorithm Working Group (AWG) Cloud Height Algorithm (ACHA), represent an effort to bridge the observational records of NASA’s Earth Observing System (EOS) and NOAA’s next-generation operational weather satellites to achieve a continuous, multi-decadal climate data record for clouds that can extend well into the 2030s. CLDPROP offers a “continuity of approach,” applying a common algorithm to both MODIS and VIIRS that attempts to mitigate known instrument differences, for instance utilizing only a subset of spectral channels available on both. The initial releases of the CLDPROP_MODIS and CLDPROP_VIIRS cloud products span the SNPP observational record (2012-present). Here, we present recent results from an ongoing evaluation of the inter-sensor continuity of the CLDPROP_MODIS and CLDPROP_VIIRS cloud optical properties datasets, i.e., cloud thermodynamic phase, optical thickness, effective particle size, and derived water path. This evaluation has focused on identifying and understanding the root causes of dataset discontinuity, including differences in sensor spatial resolution/sampling. It utilizes analysis tools developed by the NASA Atmosphere Science Investigator-led Processing System (A-SIPS), the SNPP VIIRS Atmosphere Discipline production center located at the University of Wisconsin, that include pixel-level MODIS/VIIRS co-located match files and specialized spatial and temporal statistical aggregations. The results of this evaluation are expected to inform future updates to the CLDPROP algorithms as well as the scientific user community.