Laboratory studies of exchange between a polar and a subpolar basin

Experiments on the exchange of a freshwater surface layer between two basins in a rotating tank demonstrate the contrasting roles of wind and buoyancy forces. Buoyancy-driven exchange occurs primarily in narrow boundary currents along the walls. Wind-driven exchange has a complex flow pattern with net transfer controlled by the sign of wind stress curl. Freshwater is transferred from the basin with positive curl to the one with negative curl. These results are related to freshwater flow from the Arctic Ocean to the Greenland Sea in which the southward flow of freshwater under buoyancy forces may be either increased or decreased by wind stress depending upon the sip of the curl. At present there is a negative stress curl over the Arctic Ocean which leads to a deep surface layer and no deep convection while opposite conditions in the Greenland Sea tend to remove the surface layer and allow deep convection