5. Fig. 4. The preliminary analytical solution for the nonlinear Agulhas ring production problem. Q and q are the volume fluxes of the upstream and retroflecting currents so that Q-q is the rings’ volume flux. The coastline angle relative to the east-west direction is  and the upstream vorticity is  f. Note that, for large values of , the production of rings is relatively small. It increases dramatically as the angle is reduced. For convenience, we define a critical angle as the one corresponding to the maximum gradient in (Q-q)/Q. It is around 30.