Global scale observation of the earth for climate studies

Developed since 1983 at LMD, the 3I (Improved Initialization Inversion) physical retrieval algorithm has been recently extended to the processing of NOAA (TIROS-N Operational Vertical Sounder) observations at global scale. Starting from the version implemented at ECMWF in Reading, this global scheme has been recently improved and installed on a CRAY-2. One month of observations (Feb. 1989) of NOAA-10 and 11 has recently been processed, at a spatial resolution of 100 × 100 km². A two years period should now be processed, in conjunction with the PathFinder and GEWEX-GVaP programmes. Results expected are: weekly to monthly averages of quantities like temperature structure, cloud parameters or the vertical distribution and total content of water vapor analysed in relationship to pertinent meteorological or other parameters, especially with respect to quantifying the fundamental characteristics and origines of water vapor variability.