CRIs

CrIS stands for Cross-track Infrared Sounder. It is a space-based infrared spectrometer designed to measure Earth's emitted infrared radiation with high spectral resolution in order to derive atmospheric temperature and moisture profiles, as well as information on trace gases. CrIS is a key radiometer in the NOAA/NASA Joint Polar Satellite System (JPSS) and was first flown on the Suomi National Polar-orbiting Partnership (Suomi NPP) satellite. It continues to operate on later JPSS platforms such as NOAA-20 (JPSS-1) and subsequent missions.

The instrument is nadir-looking and scans across track to produce wide swaths as the satellite orbits. CrIS covers infrared wavelengths roughly from 3.5 to 16 micrometers across three spectral bands, delivering hundreds to thousands of spectral channels per footprint. It uses a Fourier-transform spectrometer housed in a cryogenically cooled instrument, providing precise measurements of spectral radiances that are processed into calibrated Level 1 data and used to retrieve atmospheric temperature and humidity profiles, with ancillary information on some atmospheric trace constituents.

CrIS data are designed to support numerical weather prediction and climate research. When combined with microwave sounding data from ATMS and other instruments, CrIS helps constrain atmospheric state estimates across the troposphere and lower stratosphere, improving forecast skill and contributing to long-term climate datasets. Data products are distributed by NOAA/NESDIS and are used by meteorological and research communities worldwide.