Convection and deep water formation in the Arctic Ocean-Greenland Sea System

Abstract

The processes of convection and deep water formation in the Nordic Seas are reviewed. In the Arctic Ocean the formation of deep water results from brine release due to freezing, which increases the density of the shelf waters. The dense shelf waters sink on the continental slopes into the deep basins entraining ambient waters from the strongly stratified Arctic Ocean proper. In the European Polar Seas—the Nordic Seas—deep water is only formed in the Greenland Sea through haline convection, resulting in a weakly stratified water column. The exchanges through Fram Strait, the deep connection between the Arctic Ocean and the Nordic Seas are used to quantify the average rate of deep water formation. The net deep outflow from the Arctic Ocean corresponds to the production of Arctic Ocean Deep Water. By considering the total deep outflow and mixing ratios derived from θ- S characteristics of the different basins the formation rate of Greenland Sea Deep Water may by inferred. Both sources provide about 0.5 Sv making the arctic contribution to the World Ocean deep waters at least 1 Sv.