Comparison of AIRS and NAST-I Spectra and Retrievals During CRYSTAL-FACE

Abstract

During the Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL-FACE) experiment, the Proteus with the NAST-I instrument under flew the Aqua satellite on five different occasions. For the last under flight, July 26, 2002, AIRS was in a stable earth viewing operating mode . In this paper, the much higher spectral and spatial resolution airborne NAST-I radiance spectra are reduced to AIRS resolution for direct comparisons of the AIRS observed radiance spectra. Residual differences due to instrument line shape differences are accounted for using line-by-line radiative transfer calculations for both instruments using nearby radiosonde profiles. AIRS spectral radiances are also transformed to vertical temperature and moisture profiles using exactly the same statistical retrieval algorithms and training data used to process the NAST-I data during CRYSTAL-FACE field program. AIRS radiance and retrievals are compared with those of NAST-I obtained from the full resolution NAST-I data as well as from the NAST-I radiance spectra reduced to spectral and spatial resolution of the AIRS. The results of these comparisons are discussed with respect to spectral coverage and resolution, cloud effects, and other surface and atmospheric influences.