Composition of freshwater in the spring of 2014 on the southern Labrador shelf and slope

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Benetti, M., Reverdin, G., Lique, Camille, Yashayaev, I., Holliday, N. P., Tynan, E., Torres-valdes, S., Lherminier, Pascale, Treguer, P., Sarthou, G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Amer Geophysical Union 2017
• Subjects: Arctic; Baffin Bay; Greenland; Labrador Shelf; Pacific; Baffin; Labrador Sea; North Atlantic; Sea ice
• Online Access: https://archimer.ifremer.fr/doc/00365/47667/47778.pdf; https://doi.org/10.1002/2016JC012244; https://archimer.ifremer.fr/doc/00365/47667/

The Labrador Current is an important conduit of freshwater from the Arctic to the interior North Atlantic subpolar gyre. Here, we investigate the spatial variability of the freshwater sources over the southern Labrador shelf and slope during May-June 2014. Using measurements of seawater properties such as temperature, salinity, nutrients and oxygen isotopic composition, we estimate the respective contributions of saline water of Atlantic and Pacific origins, of brines released during sea ice formation, and of freshwater from sea ice melt and meteoric water origins. On the southern Labrador shelf, we find a large brine signal and Pacific Water influence indicating a large contribution of water from the Canadian Arctic. The brine signal implies that more than 4 m of sea ice formed upstream, either in the Arctic or in Baffin Bay and the northern Labrador Sea. Over the mid-shelf and slope at 52°N, we find a stronger influence of slope water from the West Greenland Current with a smaller contribution of Pacific water and no brine signal. Thus, there is advection of water from the slope region to the mid-shelf between 55°N and 52°N. Very fresh water with high meteoric content is found close to the coast in June 2014. Observations from 1995 and 2008 suggest a higher fraction of brine and Pacific water on the shelf compared to that observed in 2014.