Investigation of the Agulhas System and its Influence on the Tropical Atlantic Circulation

The Agulhas system is one of the key components forming the oceanic circulation in the Tropical Atlantic. Using different global ocean general circulation model (OGCM) setups as well as different atmospheric forcing (Reanalysis or CMIP5 data) we investigate the formation and development of the Agulhas leakage and its propagation into the Tropical Atlantic. It is shown that the simulated Agulhas leakage depends not only on the model resolution, but also on the quality of the representation of the Subtropical High in the atmospheric data. The use of the forcing obtained from the global coupled AOGCMs which tend to underestimate the South Atlantic Anticyclone leads to domination of the zonal component of the Agulhas leakage and the reduction of the northward oceanic transport. Using the results of different model simulations we try to explore the influence of the Indian Ocean inflow on important features of the general ocean circulation in the Tropical Atlantic like equatorial current system, SST distribution and Atlantic and Benguela Ninos.