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...