Methodology and Information Content of the NOAA NESDIS Operational Channel Selection for the Cross-Track Infrared Sounder (CrIS)

The Cross-track Infrared Sounder (CrIS) was launched on October 28, 2011 aboard the Suomi National Polar-orbiting Partnership platform and is scheduled to become operational in 2012. The purpose of this paper is to describe the National Oceanic and Atmospheric Administration/National Environmental Satellite and Information Service (NOAA/NESDIS) channel selection methodology applied to the CrIS instrument and to present the main spectral characteristics of the final channel subset that will be operationally distributed to the scientific community for near-real-time data assimilation and retrieval applications. We perform an information content analysis and show that this selection, composed of 399 channels, is capable of fully representing the total atmospheric variability contained in the original 1305-channel spectrum, up to instrumental noise. These results ensure that the replacement of the full 1305-channel list in favor of the proposed 399-channel selection will have no detrimental effects on data assimilation and retrieval performance.