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 ?