AN INVESTIGATION OF THE GENERAL-CIRCULATION OF THE ARCTIC-OCEAN USINGAN ISOPYCNIC MODEL

A numerical simulation of the general circulation of the Arctic Ocean is presented using Oberhuber's (1993a) coupled sea ice, mixed layer, i sopycnal general circulation model (OPYC). The model's novel feature i s that the ocean component uses density surfaces as the vertical coord inate. The model domain includes the Arctic Ocean, the Greenland-Icela nd-Norwegian (GIN) Sea, and the North Atlantic Ocean. The horizontal r esolution is 1.0 degrees in a spherical coordinate system that is rota ted with respect to geographical coordinates. The vertical is resolved into eleven isopycnal layers of which the uppermost layer is a turbul ent mixed layer. The sea ice is modelled using the dynamic-thermodynam ic model of Oberhuber which incorporates the Hibler viscous-plastic th eology. A restriction of the coupled model used here is the artificial placement of solid walls across the Bering Strait and at the equator in the Atlantic Ocean. Monthly climatological atmospheric forcing is u sed to spin the model into a cycle-stationary equilibrium. Model resul ts are presented and discussed with respect to observational and previ ous modelling studies. The simulated water mass properties and circula tion are in reasonable agreement with observations. Based on the simul ation results, new circulation patterns are suggested for the deep flo w within the Arctic Ocean. In particular, it is proposed that for the Atlantic layer and deeper waters there exists a multi-gyre circulation pattern consisting of cyclonic gyres that essentially follow contours of bottom topography.