A coupled atmosphere-ocean model of thermohaline circulation, including wind-driven gyre circulation with an analytical solution

Abstract

A parameter representing circulation due to wind forcing is added to the thermohaline circulation model of Marotzke (1996). The model consists of four boxes and is governed by a system of two differential equations governing the temperature and salinity differences between high latitude ocean and low latitude ocean boxes. The modified model is solved numerically for equilibrium solutions, and then solved analytically by the method of Krasovskiy and Stone (1998). At the maximum strength of wind-forced circulation studied, v = 5 x 10-¹¹ s-¹, a stable thermal mode equilibrium temperature difference of 25 K is calculated. Once v reaches a critical value, which is within the range of physically reasonable values, the stable haline mode equlibrium and unstable thermal mode equilibrium are no longer observed. It is concluded that strong wind-forced circulation suppresses the thermal mode equilibrium, but that more research is necessary to determine the degree to which this effect is present in the real world.