A particular feature of the Arctic Ocean is the enormous freshwater surplus. The upper Arctic Ocean receives freshwater from the Pacific inflow, through runoff from large rivers and through the distilling process of sea ice formation and melting. Nearly 11% of the global river runoff enters the Arctic, with the majority discharged to the Siberian shelves. This leads to a strongly stratified upper ocean, separating the warm and saline Atlantic waters from the sea ice and the atmosphere. The main wind-driven ice and surface circulation features are the anti-cyclonic (freshwater storing) Beaufort Gyre, and the Transpolar Drift, which drives the freshwater towards Greenland and Fram Strait from where it is eventually exported to the subpolar North Atlantic.
The Arctic freshwater inventory has substantially increased over the last decades. This accumulation might be part of a multi-decadal oscillation, which is linked to the subpolar North Atlantic, where the freshwater can influence deep-water formation. To understand the underlying mechanisms, we conduct long-term observations to document the freshwater changes and analyze the observations in close cooperation with numerical modeling efforts. The freshwater (solid and liquid) is eventually exported to the sub-polar North Atlantic. One part of the export occurs with the East Greenland Current, which episodically leaks freshwater into the interior Greenland and Icelandic seas, where it may impact deep water formation and hence the formation of overflow waters. We investigate freshwater leakage mechanisms from the East Greenland Current with a long-mission autonomous glider program.