South Atlantic Connections (SACO)

The AMOC has a major role on heat transport to high latitudes of the Atlantic Ocean, helping temperate the weather in northern Europe. Changes in deep-water formation are expected to drive major variations in the returning limb of the AMOC, e.g. a decrease would imply less subtropical water and heat arriving to high latitudes, hence increasing the density of high-latitude surface waters in what would be a regulating feedback mechanism. However, this decrease could be counteracted by an increase in the heat content of the subtropical waters and by the larger gain of radiative heat at high latitudes as a result of greenhouse and albedo changes, as well as by the associated ice melting. Either way, warming of the surface ocean would drive substantial weather changes, such as increased ocean evaporation and precipitation at high latitudes and changes in the mean position of the Intertropical Convergence Zone, with high impact in precipitation patterns of the Mediterranean and tropical regions.

One critical exchange region for both the departing and returning limbs of the AMOC takes place between the tropical and subtropical South Atlantic gyres (Fig. 1). The departing limb of the AMOC is formed by the southward propagating NADW that crosses eastward the MAR following the major passages at latitudes between 15 and 30ºS, and the returning limb of the AMOC, formed by central and intermediate waters, that follow westwards along the northern margin of the subtropical gyre (Cabré et al 2019; Arumí-Planas et al submitted). These waters come from the Indian Ocean through the warm-salty water route and the Southern Ocean through the cold-fresh water route.

https://saco-saga.ulpgc.es