Operational CrIS-VIIRS Data Integration and Collocation Algorithms

The Cross-track Infrared Sounder (CrIS) and the Visible Infrared Imaging Radiometer Suite (VIIRS) are two key instruments on board S-NPP/JPSS for imaging the Earth’s weather, climate, and environment and are used for a wide range of applications related to atmosphere, oceans, land, and hazards.  The sensor data and cloud products on the VIIRS pixels are collocated to the CrIS fields of view (FOVs) using a Lookup Table (LUT) based collocation algorithm.  These collocated VIIRS/CrIS data provide extended spectral and spatial resolution to that of CrIS.  This algorithm currently runs operationally in NESDIS within the NOAA Unique Combined Atmospheric Processing System (NUCAPS) package and provides VIIRS content to the CrIS BUFR product.  A series of updates have been applied to this collocation algorithm since its initial version.  In this paper, the details of the present algorithm are introduced and problems in the collocation processing and the related solutions are discussed.