VDM Verlag Current Retroflection from a Slanted Coastline: Modeling Agulhas Ring Injection into the South Atlantic during Glacials/Interglacials

Recent proxies suggest that, at the end of the last glacial, there was a significant increase in the injection of Agulhas rings into the South Atlantic. This event brought about a dramatic increase in the salt influx helping to re-start the Atlantic meridional overturning circulation. Until now the mechanism through which such large variation in ring production occurs has not been clear. In this book, two semi-analytical non-linear models of current retroflection from non-zonal coastline on the ¿-plane are developed to explain this phenomenon. The critical value of the coastline slant ¿ is defined, which implies restricted possibilities for ring detachment from the retroflection area in the ¿supercritical¿ range of ¿. In the case of Agulhas region, rings can be injected only if the retroflection occurs beyond specific latitude where the angle is critical. This analysis should help in understanding the regimes of ring shedding by retroflected currents and should be useful for anyone studying the dynamics of currents, meridional overturning cell in the Atlantic and climate dynamics.