Séminaire
Investigating the variability of the Agulhas leakage, the volume transport of water from the Indian Ocean to the South Atlantic Ocean, is highly relevant due to its potential contribution to the Atlantic Meridional Overturning Circulation (AMOC) and the global circulation of heat, salt and freshwater, hence to the global climate. As observations of the leakage are scattered in time, ocean model outputs are unavoidable to describe its mechanisms of variability. However, the Agulhas leakage is part of a system that still represents a challenge to modellers, because of its degree of non-linearity. As a consequence, this thesis reports the study of the mechanisms of variability of the Agulhas leakage in 6 ocean model outputs of varying resolution, vertical discretization and boundary conditions (NEMO ORCA12, ORCA025 and IPSLCM5 - HYCOM 1/12 and 1/4 - ROMS 1/12). Inter-comparing all these model outputs allows one to identify which characteristics of variability are robust, beyond the biases of each model. It also provides valuable information on the model specificities required to represent correctly the mechanisms of variability of the Agulhas leakage, hence its contribution to climate variability.