Are oceanic rings and jets statistical equilibrium states?

Oceanic flows have the property to self-organize into large scale coherent structures such as rings (robust vortices) and jets. The concomitant turbulent nature of such flows, and their self-organization property, gives a strong incentive for a statistical mechanics approach. Here we apply equilibrium statistical mechanics theory to a simple ocean model, in order to answer basic questions: What are the shape of the coherent structures? What is their drift? When are they unstable?