Investigating freshwater pathways from the East Greenland Current to deep convection regions: Drifters deployment in the shelfbreak East Greenland Current.

Continued warming in the Arctic and Subarctic regions causes enhanced Greenland Ice Sheet melt and increasing freshwater storage in the Arctic Ocean. The East Greenland Current (EGC) is the main pathway of freshwater from both these sources to the Subpolar North Atlantic. Increased input of freshwater into the more saline subpolar gyre will strengthen the local water column stratification. Model studies predict that this will inhibit convection and consequently affect the large-scale Atlantic circulation. However, most climate models do not accurately recreate the dynamic boundary that isolates the fresh surface waters of the EGC from the deep convection regions. The small scales of systems involved, with a current core width of about ~40 km and a local Rossby deformation radius of ~4 km, make it difficult for most models to resolve cross-shelf exchange. As a result, models tend to overestimate the amount of freshwater leaving the EGC and entering the subpolar gyre.

Freshwater transport estimates from observations between Fram Strait and Cape Farewell indicate that freshwater does leak out of the EGC, potentially affecting deep convection in the Greenland and Irminger Seas. However, these estimates from synoptic sections and moorings do not show the exact areas and mechanisms of exchange nor how this could change with increasing fluxes.

A new field program, starting in 2019, aims to illuminate the cross-shelf freshwater exchange of the EGC. Surface drifters were released in the shelfbreak EGC at two different locations; offshore of Tasiilaq, at approximately 65°N, and in Fram Strait, at approximately 79°N. Both drifter sets consist of 30 drifters, including SVP drifters with sea surface temperature and salinity, and GPS tracked CARTHE buoys. The first results from this experiment will be presented.