The climate community requires a consistent global multi-decadal data record of cloud and aerosol properties. As such, it is critical that VIIRS data on SNPP (and the JPSS series as available) be used as effectively as possible to extend MODIS data records beyond the EOS era.
NASA ushered in a new generation of cloud imager observations with MODIS on the EOS Terra and Aqua missions. MODIS provided unique spectral and spatial capability relative to earlier global imagers, including two shortwave infrared (SWIR) 1.6 and 2.1µm window channels that, in addition to an AVHRR heritage 3.7µm channel, provide more comprehensive cloud microphysical information. Nadir spatial resolution is at 250m (0.66, 0.86µm), 500m (SWIR), and 1km (all others). To date, the imagers have allowed for 17-yr (Terra) and 15-yr (Aqua) data records. However, detection of cloud-related trends is a multi-decadal endeavor [e.g., radiative cloud feedback detection for a range of CMIP models typically at ≳2-3 decades with current sensors, Wielicki et al., 2013]. While the Aqua and Terra missions may last several more years, the only viable imager for continuing MODIS-like global cloud records is VIIRS (375-750m nadir resolution) on Suomi NPP and the operational NOAA JPSS series (starting with the launch of JPSS-1 in late 2017 with subsequent satellites providing coverage into the mid-2030s). However, because of the absence of key spectral channels on VIIRS and a significant change in the spectral location for a key SWIR channel used for microphysical retrievals, continuity between MODIS and VIIRS cloud records is not directly possible. Providing a merged VIIRS-MODIS cloud record to serve the science community into the coming decades requires different algorithm approaches than those used for MODIS alone.