THE INFLUENCE OF THE BERING STRAIT ON THE CIRCULATION IN A COARSE RESOLUTION GLOBAL OCEAN MODEL

An ocean general circulation model of global domain, full continental geometry and bottom topography, is used to study the influence of the Bering Strait on the general circulation by comparing equilibrium solu tions obtained with and without a landbridge between Siberia and Alask a. The model is integrated with restoring boundary conditions (BC) on temperature and salinity, and later, with mixed BC in which a restorin g BC on temperature is maintained but a specified flux condition on sa linity is imposed. In both cases, the effect of the Bering Strait is t o allow a flow of about 1.25-1.5 Sv from the North Pacific to the Arct ic Ocean and, ultimately, back to the North Pacific along the western boundary current regions of the Atlantic and Indian Oceans. When a res toring BC on salinity is used, the overturning associated with North A tlantic Deep Water and Antarctic Intermediate Water formation are incr eased if the Bering Strait is present in the model geometry. The resul t of switching to a specified flux BC on salinity is to cause a transi tion in the THC in which the overturning associated with North Atlanti c Deep Water formation increases from about 12 Sv to about 22 Sv. This transition occurs in an essentially smooth fashion with no significan t variability and is about 12% smaller in magnitude if the Bering Stra it is present in the model geometry. Because the Bering Strait appears to exert some influence on the general circulation and the formation of deep water masses, it is recommended that this Strait be included i n the geometry of similar resolution models designed to study the deep ocean and potential changes in climate.