A channel selection method for hyperspectral atmospheric infrared sounders based on layering

This study introduces an effective channel selection method for hyperspectral infrared sounders. The method is illustrated for the Atmospheric InfraRed Sounder (AIRS) instrument. The results are as follows. (1) Using the improved channel selection (ICS), the atmospheric retrievable index is more stable, with the value reaching 0.54. The coverage of the weighting functions is more evenly distributed over height with this method. (2) Statistical inversion comparison experiments show that the accuracy of the retrieval temperature, using the improved channel selection method in this paper, is consistent with that of 1D-Var channel selection. In the stratosphere and mesosphere especially, from 10 to 0.02 hPa, the accuracy of the retrieval temperature of our improved channel selection method is improved by about 1 K. The accuracy of the retrieval temperature of ICS is also improved at lower heights. (3) Statistical inversion comparison experiments for four different regions illustrate latitudinal and seasonal variations and better performance of ICS compared to the numerical weather prediction (NWP) channel selection (NCS) and primary channel selection (PCS) methods. The ICS method shows potential for future applications.