Optimal parameterization of the spectra of outgoing thermal radiation with the data of the IKFS-2 spaceborne IR sensing device taken as an example

Abstract

From the ensemble of the calculated spectra of the outgoing thermal radiation in the 660- to 2010-cm−1 range (2311 realizations) simulating global measurements by the IKFS-2 spaceborne device, the informativeness of the measurements of the outgoing thermal radiation has been analyzed in terms of Kozlov’s data volume, the degrees of freedom, and the Shannon information gain. In the entire spectral range (660–2010 cm−1), there are 106 independent parameters in the measurements of the outgoing radiation. The accuracy of the optimal parameterization of the spectral behavior of the radiation based on the radiation resolution into eigenvectors of the spectral covariance matrix has been analyzed. It is shown that to reach an rms error of the parameterization comparable with the random measurement noise for different spectral regions, it is sufficient to use from 20 to 50 first eigenvectors.