Atmospheric property retrievals from infrared atmospheric sounding interferometer (IASI)

Abstract

Retrieving atmospheric and surface properties from hyperspectral sensors is a challenging task due to the requirement of performing extensive radiative transfer calculations for thousands of channel radiances. We will present a retrieval algorithm, which uses a Principal Component-based Radiative Transfer Model (PCRTM) to perform radiative transfer calculation in Empirical Orthogonal Functions (EOF) domain. By compressing thousands of channel radiances into one hundred EOFs, the dimensionality of the problem is greatly reduced while the information content is preserved. The PCRTM provides the EOF coefficients and associated derivatives with respect to atmospheric and surface parameters needed by the inversion algorithm. The inversion algorithm is based on a non-linear Levenberg-Marquardt method with climatology covariance and a priori information as constraints. We will show results obtained from data collected during the Joint Airborne IASI Validation Experiment (JAIVEx). The campaign took place in late April and early May of 2007. Spectra observed by Infrared Atmospheric Sounder Interferometer (IASI) onboard of METOP-A satellite will be used to retrieve atmospheric (temperature, moisture, and trace gas profiles, cloud top, cloud particle size and cloud optical depth) and surface properties (surface skin temperature and surface emissivity). Collocated radiosondes and dropsondes will be used in retrieval product inter-comparisons and validation.