Multi-Eady models of surface and deep instabilities

Abstract:

There is growing evidence that the upper ocean is host to vigorous turbulence
generated by baroclinic instabilities of lateral density fronts. We present a
QG model for studying baroclinic instabilities of a weakly stratified surface
layer coupled to a deeper layer. The general model has constant N layers,
rather than constant density, and can accommodate density jumps as well to
represent the seasonal thermocline. On the f-plane, this "stacked Eady" model
is exact; on the beta-plane, it can still be used as an approximation which,
unlike the standard layer model, allows for instabilities associated with SST
gradients. We discuss the linear instabilities and a numerical example of the
fully-developed turbulence.