Abstract

The ARA (Atmospheric Radiation Analysis) group at LMD has developed a good experience in the retrieval of atmospheric temperature and moisture profiles with the "3I" (Improved Initialization Inversion) algorithm using TOVS observations. However, for operational numerical weather prediction or climate researches, the weaknesses of this kind of observations are now well recognized: too limited vertical resolution and accuracy (= 2K rms in temperature and 20-30 % in water vapor profiles). The high spectral resolution infrared sounders like AIRS (Atmospheric Infrared Sounder) or IASI (Improved Atmospheric Sounding in the Infrared) will provide a great improvement in the retrieval of atmospheric and surface properties. Such an increase in spectral resolution in the observations will be successful only if the processing tools are adequate. Among them are : a fast and accurate radiative transfer model, a carefully selected set of channels throughout the infrared spectrum, a well elaborated retrieval/assimilation procedure. This paper presents an overview of these developments, a special emphasis being given to the latter one. Results recently obtained within the frame of the activities of the AIRS scientific team in cooperation with GLA (Goddard Laboratory for Atmosphere) will be discussed.

© 1993 Optical Society of America