The isolated initial vortices that are resonantly damped on the f plane by their initial state and become unstable on the beta plane due to nonlinear interaction between the symmetric vortex and the beta gyres are discussed. The initial model states are made barotropic by having the same wind in each of the two layers, while the mass gyres differ in order to apply the barotropic theory. The model have two homogeneous incompressible layers with a free surface and is capped with an inert third layer. Resonant damping theory is applied by finding the positions of the potential vorticity (PV) minimum and the critical radius at each level each 24 h out to 192 h.
