VIIRS-CRIS/SNPP Cloud Mask + Sounder 6-Min L2 Swath 750m V2

The Suomi National Polar-orbiting Partnership (SNPP) Visible Infrared Imaging Radiometer Suite (VIIRS) NASA Level-2 (L2) Cloud Mask + Sounder is a new continuity product that leverages the synergy between the VIIRS instrument’s higher spatial resolution and the Cross-track Infrared Sounder (CrIS) instrument’s higher spectral resolution. This product is the result of a data fusion process between an imager (VIIRS) and a hyperspectral sounder (CrIS), which provides improved sensitivity in nighttime and polar regions utilizing additional information content from the sounder’s absorption channels (water vapor and carbon dioxide). This continuity product is designed to sustain the long-term records of both Moderate Resolution Imaging Spectroradiometer (MODIS) and VIIRS heritages but with cloud mask performance similar to the full-resolution MODIS cloud mask.

CLDMSK_L2_VIIRS-CRIS_SNPP is the shortname for the SNPP VIIRS version of this product that is derived from the MODIS-VIIRS cloud mask (MVCM) continuity algorithm, which itself is based on the MODIS (MOD35) algorithm. The MODIS (from Terra and Aqua missions) and VIIRS (from SNPP and Joint Polar Satellite System (JPSS) missions) data-derived cloud mask products use the MVCM algorithm. Implemented to consistently handle MODIS and VIIRS inputs, the v2.0 SNPP VIIRS Cloud Mask + Sounder collection products use calibration-adjusted NASA VIIRS L1B as inputs. The nominal spatial resolution of the SNPP VIIRS L2 Cloud mask is 750 meters at nadir. The v2.0 collection starts from March 1, 2012 (2012-061). The L2 netCDF product, acquired and processed every 6 minutes.

Consult the [MODIS-VIIRS Cloud Mask Product User Guide](https://ladsweb.modaps.eosdis.nasa.gov/api/v2/content/archives/Document%20Archive/Science%20Data%20Product%20Documentation/MVCM_User_Guide_Oct_2020.pdf) for additional information regarding the transition from the MODIS-MOD35 to the MVCM algorithm, inputs to MVCM, output files, file naming conventions, quality flags, and validation. Users are also encouraged to consult the MOD35 Algorithm Theoretical Basis Document ([ATBD](https://modis-atmosphere.gsfc.nasa.gov/sites/default/files/ModAtmo/MOD35_ATBD_Collection6_0.pdf)) and the [MODIS Atmosphere QA Plan](https://modis-atmosphere.gsfc.nasa.gov/sites/default/files/ModAtmo/QA_Plan_C6_Master_2015_05_05_0.pdf) for relevant information that are applicable to the NOAA-20 VIIRS Cloud Mask product.