On the evolution of intensive cyclonic-anticyclonic vortex pairs

Abstract

Intensive baroclinic eddies in the ocean are shown to have a new type of nonlinearity which is not taken into account by the traditional quasi-geostrophic equation. The evolution and decay of dipole eddies are investigated using a generalized near-geostrophic model. The time interval after which the traditional approach is no longer valid is estimated analytically. Two sets of numerical calculations are presented. In the first one, the evolution of “modons” is simulated and shown to depend on their intensity and size. It is found that additional nonlinear effects change the trajectory of relatively small eddies rather than their structure. In the second set of experiments, we consider the process of coupling of initially monopole eddies in a shear flow. © 1989, Elsevier B.V. All rights reserved.