CMIP3 and CMIP5 representation of sea surface temperature in the Tropical Atlantic Ocean

Abstract

This study evaluates WCRP-CMIP3 and CMIP5 representation of the Sea Surface Temperature (SST) in the Atlantic Tropical Basin. The Atlantic Ocean presents thermal variability modes on intraseasonal, interannual and decadal time-scales that affect the climate of the North Atlantic, Caribbean, Western Africa, Northeast Brazil, the Gulf of Guinea Region and Southeast Atlantic (region of the Angolan resurgence). Two main SST modes in the Atlantic are the equatorial and meridional dipoles. These principal modes of SST interannual variabilities are investigated principally by empirical orthogonal function analysis (EOFs) to periods December-January and March-May. For the period of March-May, this study too analyses the relationships of these modes from coupled models of WCRP as rainfall in Northeastern Brazil compared to the observations (1971-2000 - ERSST). This investigation showed principally  that although some models showed high value correlations (above 0.8 in absolute value) for both CMIP3 and CMIP5 with observations using their first two auto values EOFs coefficients of SST in the Tropical Atlantic basin, the simulations in most CMIP3-5 models do not represented the spatial thermal configuration in the basin compared to the observations, and also largely do not reproduce the pattern of correlation between to March-May between precipitation in northern of the NEB and the TSMs in the Tropical Atlantic.