The inter-ocean exchange of heat and salt around South Africa is recognised to be a key link in the maintenance of the global overturning circulation of the ocean and plays a major role in global climate. Most of the Indian Ocean leakage into the South Atl antic takes place by the shedding of Agulhas rings at the Agulhas Current Retroflection. The Agulhas system is known by its strong variability of both ecosystem and physical dynamics at different spatial and temporal scales. In this project we want to anal yse the dynamical behavior of the southwestern part of the subtropical gyre in the Indian Ocean, that directly feeds the inter-ocean exchange. Unique of the project is the focus on both physical dynamical aspects as well as on the distribution of chlorophy ll a. A connection has been found between upstream anomalies in the Agulhas Current, originating in the Mozambique Channel and from the East Madagascar Current, and the shedding of Agulhas rings. However, the role of the gyre is still unclear. Especially t he extremely strong recirculation gyre in the southwest corner of the gyre seems to have a large influence on the dynamics, both from a physical and from a biological point of view. Sometimes, early retroflection of the Agulhas Current hampers the shedding of Agulhas rings, and thus has serious consequences for the physical and biological characteristics of the waters in the South Atlantic and in the Agulhas Return Current. To investigate these phenomena physical and biological interactions will be studied from in situ measurements, multi-sensors data sets and modelling at European level. Prof. Dr. De Ruijter's research group is presently working on the connection between the large-scale variability in the Indian Ocean (Indian Ocean Dipole/El Nino Southern O scillation) and the mesoscale variability around Madagascar. This gives us a unique opportunity to tackle the whole chain from the large-scale variability in the Indian Ocean to the inter-ocean exchange.
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