Evaluating the NASA Aqua MODIS/SNPP VIIRS climate data record continuity cloud products

Version 1 of the NASA Aqua MODIS/SNPP VIIRS climate data record continuity cloud products (CLDPROP) was publicly released in April 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 instrument differences, including utilizing a subset of spectral channels available on both. The initial Version 1 release of the CLDPROP_MODIS and CLDPROP_VIIRS data records span the SNPP observational record (2012-present). Here, we present an evaluation of the inter-sensor continuity of the CLDPROP_MODIS and CLDPROP_VIIRS cloud optical properties products, i.e., cloud thermodynamic phase, optical thickness, effective particle size, and derived water path. This evaluation includes analyses of pixel-level MODIS/VIIRS co-locations and spatial and temporal aggregated statistics, and focuses on identifying and understanding the root causes of product discontinuity. The results of this evaluation are expected to inform future updates to the CLDPROP products as well as the scientific user community.