THE MOTION OF A NONISOLATED VORTEX ON THE BETA-PLANE

The trajectory of a non-isolated monopole on the beta-plane is calcula ted as an asymptotic expansion in the ratio of the strength of the vor tex to the beta-effect. The method of matched asymptotic expansions is used to solve the equations of motion in two regions of the flow: a n ear field where the beta-effect enters as a first-order forcing in rel ative vorticity, and a wave field in which the dominant balance is a l inear one between the beta-effect and the rate of change of relative v orticity. The resulting trajectory is computed for Gaussian and Rankin e vortices.