Extreme wind events responsible for an outsized role in shelf-basin exchange around the southern tip of Greenland.

The coastal circulation around Southern Greenland transports fresh, buoyant water masses from the Arctic and Greenland Ice Sheet near regions of convection, sinking, and deep-water formation in the Irminger and Labrador Seas. Here, we track the pathways and fate of these fresh water masses by initializing synthetic particles in the East Greenland Coastal Current on the Southeast Greenland shelf and running them through altimetry-derived surface currents from 1993 to 2021. We report that the majority of waters (83%) remain on the shelf around the southern tip of Greenland.

A continuous pathway for fresh water along the East Greenland shelf.

Export from the Arctic and meltwater from the Greenland Ice Sheet together form a southward-flowing coastal current along the East Greenland shelf. This current transports enough fresh water to substantially alter the large-scale circulation of the North Atlantic, yet the coastal current's origin and fate are poorly known due to our lack of knowledge concerning its north-south connectivity. Here, we demonstrate how the current negotiates the complex topography of Denmark Strait using in situ data and output from an ocean circulation model.

No inter-gyre pathway for sea-surface temperature anomalies in the North Atlantic.

Recent Lagrangian analyses of surface drifters have questioned the existence of a surface current connecting the Gulf Stream (GS) to the subpolar gyre (SPG) and have cast doubt on the mechanism underlying an apparent pathway for sea-surface temperature (SST) anomalies between the two regions. Here we use modelled Lagrangian trajectories to determine the fate of surface GS water and satellite SST data to analyse pathways of GS SST anomalies. Our results show that only a small fraction of the surface GS water reaches the SPG, the water that does so mainly travels below the surface mixed layer, and GS SST anomalies do not propagate into the SPG on interannual timescales.