A Zonally Averaged Ocean Model for the Thermohaline Circulation. Part II: Interocean Circulation in the Pacific-Atlantic Basin System

Abstract The zonally averaged, latitude-depth ocean model, developed in Part I, is extended to a two-basin system representing the Atlantic and Pacific. Steady states are calculated under two different surface boundary conditions to study a possible global thermohaline circulation linking the Pacific and the Atlantic. If the surface temperature and salinity profiles are identical functions of latitude in both the Pacific and the Atlantic, the steady state under restoring boundary conditions consists, in spite of the different basin extensions, of a two-cell structure in each basin. Upon switching to mixed boundary conditions the state is unstable, and a one-cell circulation with downwelling at high northern latitudes develops in both basins. For a realistic surface salinity profile that is fresher in the Pacific, the steady state under restoring boundary conditions is completely different. It exhibits a global thermohaline circulation with strong interocean man exchange. Deep water is formed primarily in ...