Information Content Analysis of CLARREO Far-IR and Mid-IR Spectral Regions

The Climate Absolute Radiance and Refractivity Observatory (CLARREO) will have spectrally resolved reflected solar and emitted infrared radiances and GPS measurements that will be used to detect climate trends and to test, validate, and improve climate prediction models. We will present our studies on the information content of the IR instrument using partial derivatives of the infrared radiances with respect to measured atmospheric parameters such as atmospheric temperature and moisture profiles. Averaging kernels and degree of freedom of the CLARREO IR instrument as a function of spectral resolution, band coverage, and instrument noise will be presented. We will also discuss how to explore climate signals from the spectrally resolved CLARREO IR radiance spectra. Since CLARREO will be used for calibrating other satellite instruments, accounting for the differences between the spectral response functions of the CLARREO instrument and the sensors being calibrated is very important. We will show the impact of the CLARREO IR spectral resolution on the accuracy of calibrating broadband radiance measurements such as those measured by MODIS. Methods have been developed to account for a scene-dependent the errors that could be introduced by the spectral matching process.