How does Arctic Ocean outflow affect the North Atlantic Deep Water?

The outflow from the Arctic Ocean plays a critical role in the formation of North Atlantic Deep Water (NADW), a key component of the global thermohaline circulation.1

Warm waters from the Atlantic enter the Greenland-Iceland-Norwegian (GIN) Sea and encounter colder, fresher water and ice drifting southward from the Arctic. As these waters meet, the Atlantic water cools, becomes denser, and sinks, contributing to the formation of the NADW that circulates throughout the world's oceans.12

However, this process is sensitive to the balance of salinity and density. The Arctic outflow acts as a "cap" of lower-salinity water; if the export of fresh water and ice from the Arctic increases, it can reduce the surface salinity and density of the North Atlantic. This inhibits the water's ability to sink, potentially weakening or shutting down the convection processes that drive the NADW. Conversely, a decrease in this freshwater export might allow for more active convection and ventilation in the region.123