Impact of cooling on the water mass exchange of Agulhas rings in a high resolution ocean model

The leakage of water from three Agulhas rings has been studied in a high resolution global ocean model using a Lagrangian particle following technique. A bowl shaped ring boundary that reaches a radius of 140 km and a depth of 800 m separates regions of fast and slow leakage. The dilution of Agulhas ring water generally increases with depth, but a shallow secondary circulation enhances leakage in the upper 150 m. Strong surface cooling upsets the horizonal pressure gradient which is balanced by subinertial motions that act to form this shallow overturning cell.