The goal of creating this product is to allow users to begin working with data from the CrIS instrument on-board the recently launched NOAA-21 / JPSS-2 (J2) satellite. The J2 beta product was generated using an updated version of the software that is used to generate the Version 3 SNPP and JPSS-1 (J1) products, which are currently available from GES DISC. Changes were made to allow J2 processing, but the underlying algorithm theoretical basis remains the same. It should be noted that work on refining the J2 calibration parameters is ongoing, and the parameters used in this release are preliminary. A future Version 4 set of products is planned for release after J2 has reached validated status, which will include optimized J2 parameters and will use a single software version for all three instruments incorporating various algorithm improvements.
The Cross-track Infrared Sounder (CrIS) Level 1B Full Spectral Resolution (FSR) data files contain radiance measurements along with ancillary spacecraft, instrument, and geolocation data of the CrIS instrument on the Joint Polar Satellite System-2 (JPSS-2) platform. This platform is also know as NOAA-21 (National Oceanic and Atmospheric Administration). The JPSS-2 mission with CrIS instrumentation is a follow-on to the Suomi National Polar-orbiting Partnership (SNPP) mission. The CrIS instrumentation and data processing system is nearly identical to that of the SNPP satellite.
CrIS is designed to be used with the ATMS (Advanced Technology Microwave Sounder) instrument. Processing the data from both of these instruments together is referred to as CrIMSS (Cross-Track Infrared and Microwave Sounder Suite).
The FSR files have 2,223 channels (2211 apodized channels): 637 (633) shortwave channels from 3.9 to 4.7 microns (2555 to 2150 cm-1), 869 (865) midwave channels from 5.7 to 8.05 microns (1752.5 to 1242.5 cm-1), and 717 (713)longwave channels from 9.1 to 15.41 microns (1096.25 to 648.75 cm-1). Each CrIS field-of-regard (FOR) contains 9 field-of-views (FOVs) arranged in a 3X3 array. The Level 1B files contain 30 FORs in the cross track direction and 45 in the along track direction. Data products are constructed on six minute boundaries.
An issue has been observed in J2 CrIS data that impacts calibration of observations for a period of several minutes during each orbit. The issue occurs in the southern hemisphere during the descending part of the orbit, near a satellite solar zenith angle of -118 degrees. There is significant variability in affected latitudes throughout the year. The issue is indicated by non-zero quality flags in the Level 1B product. The root cause is believed to be variation in calibration views due to rapid instrument temperature changes after the J2 satellite passes from the Earth's shadow into direct sunlight. Potential solutions are being evaluated for implementation in a future product version.
If you were redirected to this page from a DOI from an older version, please note this is the current version of the product. Please contact the GES DISC user support if you need information about previous data collections.