A model study of temperature anomaly propagation from the subtropics to tropics within the South Atlantic thermocline

Abstract

A water mass flow formed by the Benguela Current and the South Equatorial Current connects the eastern subtropics to the western tropics through the Atlantic upper thermocline. We perform a process study with an Atlantic OGCM to examine whether and how synthetic subtropical mixed layer heat anomalies would employ this corridor to reach low-latitudes. Our results suggest that it is a realistic scenario and that the time scale and trajectory of the movement can be explained to first approximation by time-mean flow advection, since salinity compensation is tempering the density perturbation. In addition, wave processes seem to influence strongly the evolution of the intensity and the shape of the anomalies. It is apparent that an approach using both perspectives is necessary to fully understand and predict subsurface oceanic teleconnections.