The Suomi National Polar-orbiting Partnership (SNPP) Visible Infrared Imaging Radiometer Suite (VIIRS) NASA Level-3 (L3) daily water vapor product is an aggregation dataset derived from the SNPP VIIRS L2 Water Vapor product. “D3” refers to a daily-produced L3 product, which is processed to generate a global 0.5°by 0.5°gridded daily mean data separated by day and night. It contains the following six Science Data Sets (SDS) that each carry a common set of statistical variables for each grid cell:

1. day_atmosphere_water_vapor_content_nucaps_bg (NUCAPS¹ retrieval)
2. day_atmosphere_water_vapor_content_viirs_nucaps (VIIRS + NUCAPS retrieval)
3. day_atmosphere_water_vapor_content_viirs_only (VIIRS-only retrieval)
4. night_atmosphere_water_vapor_content_nucaps_bg (NUCAPS retrieval)
5. night_atmosphere_water_vapor_content_viirs_nucaps (VIIRS + NUCAPS retrieval)
6. night_atmosphere_water_vapor_content_viirs_only (VIIRS-only retrieval)

Each SDS above includes the following statistical variables: mean, n_points, standard_deviation, sum, and sum_squares. The temporal range for this SNPP VIIRS L3 daily product, in Network Common Data Form (netCDF), starts from March 1, 2012 (Julian day – 061). Version-1 defines the current collection for the water vapor suite that is available from the LAADS DAAC.

Consult the SNPP VIIR Water Vapor product user guide and Algorithm Theoretical Basis Document for additional information regarding the water vapor product suite, its algorithm, global attributes, data field attributes, SDS names and descriptions, quality flags, etc.

Notes

1. NUCAPS: NOAA Unique CrIS ATMS processing System: A NOAA-developed system that produces: (1) spectrally and spatially thinned radiances, (2) retrieved products such as profiles of temperature, moisture, trace gases and cloud-cleared radiances, and (3) global validation products such as radiosonde matchups and gridded radiances and profiles.