Ekman heat transport for slab oceans

Abstract

A series of schemes designed to include various representations of the Ekman-driven heat fluxes in slab-ocean models is introduced. They work by computing an Ekman mass flux, then deducing heat fluxes by the surface flow and an opposite deep return flow. The schemes differ by the computation of the return flow temperature: either diagnosed from the SST or given by an active second layer. Both schemes conserve energy, and use as few parameters as possible. Simulations in an aquaplanet setting show that the schemes reproduce well the structure of the meridional heat transport by the ocean. Compared to a diffusive slab-ocean, the simulated SST is more flat in the tropics, and presents a relative minimum at the equator, shifting the ITCZ into the summer hemisphere. In a realistic setting with continents, the slab model simulates correctly the mean state in many regions, especially in the tropics. The lack of other dynamical features, such as barotropic gyres, means that an optimal mean-state in regions such as the mid-latitudes will require additional flux corrections. © 2011 Springer-Verlag.