Merger and Alignment of QG Ellipsoidal Vortices

Coherent vortices are an important component of the mesoscale eddy variability of the ocean. Here we investigate the interaction of three-dimensional quasigeostrophic (qg) vortices in the ellipsoidal moment approximation and compare with simulations of the qg fluid equations. We find a clear separation between the process of merger and alignment. Merger corresponds to a transition to strong chaos, while alignment is a more subtle phenomenon involving vortex Rossby waves.