Transport and fate of the Labrador Coastal Current

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The Labrador Coastal Current (LCC) transports fresh outflow from the Canadian Arctic Archipelago, Hudson Bay, and the Greenland Ice Sheet southward along the Newfoundland and Labrador Shelf. If mixed offshore into the boundary current of the subpolar gyre, the fresh water in the LCC has the potential to stratify the upper ocean and alter the Atlantic Meridional Overturning Circulation (AMOC). Yet very little is currently known about the transport of the LCC and whether the LCC interacts with the large-scale North Atlantic circulation, or remains on the shelf around the Grand Banks. This project would study the fate of the LCC and its transport along the Canadian Labrador and Newfoundland coastlines. Using a combined Eulerian and Lagrangian observational study, the project would examine whether the fresh, buoyant water in the LCC moves off the shelf to join the Labrador Current, hypothetically due to a combination of the region’s complex bathymetry and strong wind forcing. The work would support an early career researcher, provide project material for a summer undergraduate intern, and involve 7 students with cruise experience as watch standers.Four moorings will be deployed in summer for one year, along the Canadian Atlantic Zone Monitoring Program (AZMP) Seal Island hydrographic section inshore of Hamilton Bank, which will provide the first continuous volume and freshwater transport time series of the LCC. In addition, 46 surface drifters will be released into the LCC, in subsets at 15 day intervals, by three moored Submerged Autonomous Launch Platforms (SALPs). Two cruises will be conducted along the deployment and recovery efforts, collection high-resolution shipboard ADCP and CTD surveys of the Newfoundland and Labrador Shelf. Together with the historical AZMP hydrographic sections, the project will quantify transport and track the pathways and fate of the fresh water in the LCC, and will identify hot spots of shelf-basin exchange. Timing of the NASA Surface Water and Ocean Topography (SWOT) satellite launch and three-month “Fast- Sampling Phase” with daily flyovers may coincide with the drifter releases, and would provide high-resolution sea-surface height (SSH) and surface geostrophic velocities of the inner shelf, potentially broadening the spatial and temporal extent of this targeted study.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.