Variation of fresh water in the western Nordic Seas

U. Schauer, G. Budeus and K. Latarius

In this project we will measure fluctuations of the fresh water in the western Nordic Seas and analyse the underlying processes. Fresh water input to the Arctic Mediterranean is large: The Arctic Ocean receives huge amounts of fresh water by continental runoff and by import from the Pacific Ocean and fresh water is concentrated at the surface through sea ice formation. The Nordic Seas, particularly the East Greenland Current, constitute an important conduit for this fresh water from the Arctic Ocean towards the North Atlantic. Part of the fresh water carried in the East Greenland Current in variable fractions of sea ice and in liquid form enters the central Nordic Seas via branching of the current and through eddies. It controls the intensity of deep water formation and dilutes the water masses which result from convection. The last decades showed a strong freshening in the Arctic while the North Atlantic, and also the Nordic Seas, were rather more saline suggesting complex long-term large-scale interactions.

In the coming years, we will comprehend the Nordic Seas Argo program by applying new autonomous technology and carrying out season-long glider missions to capture the fresh water inventory, its spatial distribution and its pathways between the East Greenland Current and the interior Greenland and Icelandic seas. The new measurements and existing data will serve as basis for understanding the causes of the fresh water variability and their consequences for the North Atlantic circulation and deep water formation.

Figure: The propagation of the „Great Salinity Anomaly“ of the 1970s (taken from Ellett and Blindheim., 1992) and proposed glider surveys in red.