The Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) NASA Level-2 (L2) Cloud Mask is one of four continuity products designed to sustain the long-term records of both MODIS and Visible Infrared Imaging Radiometer Suite (VIIRS) heritages. CLDMSK_L2_MODIS_Aqua is the shortname for the Aqua MODIS version of the Cloud Mask continuity product derived from the MODIS-VIIRS cloud mask (MVCM) algorithm, which itself is based on the MODIS (MOD35) algorithm. MVCM describes a continuity algorithm that is central to both MODIS data (from Terra and Aqua missions) and VIIRS data (from SNPP and Joint Polar Satellite System missions). Implemented to consistently handle MODIS and VIIRS inputs, the Aqua MODIS version-2.0 (v2.0) collection products use MODIS 6.1 L1B as input. The nominal spatial resolution of the Aqua MODIS L2 Cloud Mask is 1 km at nadir. The v2.0 collection starts from July 4, 2012 (2002-185).

The L2 netCDF product, acquired and processed every 5 minutes, contains the following three data groups and Science Data Set (SDS) layers in each group:

Geophysical data

• MODIS Cloud Mask and Spectral Test Results
• MODIS Clear Sky Confidence
• MODIS Integer Cloud Mask
• Quality Assurance for MODIS Cloud Mask

Geolocation data

• Latitudes of pixel locations
• Longitudes of pixel locations
• Sensor azimuth angle at pixel locations
• Sensor zenith angle at pixel locations
• Solar azimuth angle at pixel locations
• Solar zenith angle at pixel locations

Scanline attributes

• Scan start time (TAI93)

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 and the MODIS Atmosphere QA Plan (see links below) for relevant information that are applicable to the Aqua MODIS Cloud Mask product.