ON THE CONTRIBUTION OF 20 YEARS OF ATSR DATA AND GEODESIC P-SPLINE EFFICIENT SPATIAL SMOOTHING METHOD TO ITCZ TREND ANALYSIS

The Intertropical Convergence Zone (ITCZ) is the region where the trade winds converge. It plays a key role in the general circulation of the atmosphere and understanding its variability is essential for improving global climate models. We use the Total Column Water Vapour (TCWV) global distribution and the complementary cloud occurrence information to investigate the meridional migration of the ITCZ over 20 years from 1991 to 2012. The TCWV dataset was obtained from the analysis of the thermal infrared measurements acquired by the Along Track Scanning Radiometer (ATSR) instruments in the frame of the Long Term Data Preservation ESA programme. The huge amount of data used for the ITCZ analysis required the application of a method to efficiently extract the information. We use a Geodesic P-spline spatial smoothing method and the posterior probability distribution for identification of the ITCZ. Here we show the results of this work and the comparison with independent ITCZ datasets.