The National Oceanic and Atmospheric Administration-20 (NOAA-20) Visible Infrared Imaging Radiometer Suite (VIIRS) NASA Level-2 (L2) Cloud Mask is one of four continuity products designed to sustain the long-term records of both Moderate Resolution Imaging Spectroradiometer (MODIS) and VIIRS heritages. CLDMSK_L2_VIIRS_NOAA20 is the shortname for the NOAA-20 VIIRS incarnation of the Cloud Mask continuity 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 NOAA-20 VIIRS v2.0 collection products use calibration-adjusted NASA VIIRS L1B as inputs. The nominal spatial resolution of the NOAA-20 VIIRS L2 Cloud mask is 750 meters at nadir. The v2.0 collection, which starts from February 17, 2018 (2018-048), also contains a high-resolution I-band (375 m) daytime cloud mask. The L2 netCDF product, acquired and processed every 6 minutes.

Consult the MODIS-VIIRS Cloud Mask Product User Guide 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) and the MODIS Atmosphere QA Plan for relevant information that are applicable to the NOAA-20 VIIRS Cloud Mask product.