A two layer model of a non diffusive thermocline (Formerly paper P5.16)

A non diffusive idealized ocean is represented by a two layer primitive equation isopycnal model. We consider a basin extending from the equator to midlatitudes. Surface forcing and a crude parameterization of a mixed layer induce the isopycnal interface to outcrop, therefore providing a simple model of a thermocline. A satisfactory wind-driven steady state circulation is reproduced, including a subtropical gyre and a simplified equatorial circulation.

In this idealized setting, we wish to investigate what sets the structure of the equatorial thermocline and its relation to the midlatitude thermocline. To this end, sensitivity to initial stratification and to external parameters such as winds and thermal forcing is explored and the adjustment process that leads to a steady state from an initial condition of rest will be investigated.

The midlatitude steady state thermocline is well described by an analytical sverdrupian model; at the equator the results show that the absolute depth of the thermocline is constrained by the need to balance buoyancy sources and sinks.