CLDPROP_D3_VIIRS_SNPP - VIIRS/SNPP Cloud Properties Level 3 daily, 1x1 degree grid

The Suomi National Polar-orbiting Partnership (SNPP) Visible Infrared Imaging Radiometer Suite (VIIRS) NASA Level-3 (L3) daily Cloud Properties is one of two continuity products designed to sustain the long-term records of both Moderate Resolution Imaging Spectroradiometer (MODIS) and VIIRS heritages. CLDPROP_D3_VIIRS_SNPP is the shortname for the SNPP VIIRS incarnation of the daily Cloud Properties continuity product. CLDPROP is used to represent Cloud Properties, which includes both Cloud-Optical Property (COP) and Cloud-Top Property (CTP) parameters. “D3” refers to a daily-produced L3 product. This product ensures continuity of approach through a common algorithm that is applicable to both MODIS and VIIRS data by leveraging only those spectral channels that are common to both instruments.

The L3 Cloud Properties product is derived from the SNPP/VIIRS L2 Cloud Properties product (CLDPROP_L2_VIIRS_SNPP), which is a swath-level dataset that is produced every 6 minutes. It contains 128 science data sets (SDS/parameters) that comprise 837 variables (statistics). The number of science parameters broadly breakdown thus:

• Cloud-Top Properties: 21
• Cloud-Optical Properties: 103
• Solar and Sensor Angles: 4

Each science parameter includes a combination of the following statistical variables:

• Mean, Standard Deviation, Pixel Count, Sum, and Sum Squares
• Parameters of log-normal distributions
• Fraction of pixels that satisfy some condition (e.g., liquid water clouds, ice clouds, etc.)
• Histograms of the sampled Level-2 pixels within each grid-cell
• Joint histograms that are derived by comparing one science parameter to another; this may also involve computing statistics for a subset that satisfies some condition.

Consult the L3 CLDPROP User Guide for details regarding how the L3 daily statistics are computed, and to learn more about the gridding and sampling protocols specific to this product besides a number of other topics germane to the user community. Each calendar year includes 365 granules. The version 1.1 collection of this product starts from March 1, 2012 (Julian day 061).