Evolution of the freshwater coastal current at the southern tip of Greenland

• Published in: Journal of Physical Oceanography
• Main Authors: Lin, Peigen, Pickart, Robert S., Torres, Daniel J., Pacini, Astrid
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Meteorological Society 2018
• Subjects: Boundary currents; Coastal flows; Instability; Ocean circulation; Potential vorticity; Transport; Arctic; Greenland; Cape Farewell; Ice Sheet; Labrador Sea
• Online Access: https://hdl.handle.net/1912/10599

Author Posting. © American Meteorological Society, 2018. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 48 (2018): 2127-2140, doi:10.1175/JPO-D-18-0035.1. Shipboard hydrographic and velocity measurements collected in summer 2014 are used to study the evolution of the freshwater coastal current in southern Greenland as it encounters Cape Farewell. The velocity structure reveals that the coastal current maintains its identity as it flows around the cape and bifurcates such that most of the flow is diverted to the outer west Greenland shelf, while a small portion remains on the inner shelf. Taking into account this inner branch, the volume transport of the coastal current is conserved, but the freshwater transport decreases on the west side of Cape Farewell. A significant amount of freshwater appears to be transported off the shelf where the outer branch flows adjacent to the shelfbreak circulation. It is argued that the offshore transposition of the coastal current is caused by the flow following the isobaths as they bend offshore because of the widening of the shelf on the west side of Cape Farewell. An analysis of the potential vorticity shows that the subsequent seaward flux of freshwater can be enhanced by instabilities of the current. This set of circumstances provides a pathway for the freshest water originating from the Arctic, as well as runoff from the Greenland ice sheet, to be fluxed into the interior Labrador Sea where it could influence convection in the basin. Funding for this project was provided by the National Science Foundation under Grant OCE-1259618. 2019-03-11