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Quantification of lateral exchanges of heat and salt between boundary currents and the Central Labrador Sea

Department of Oceanography, Dalhousie University, Halifax
Supervisor: Barry Ruddick
Co-supervisors: Maren Walter (University of Bremen), Monika Rhein (University of Bremen)

Project description:

Several different ocean currents enter the Labrador Sea, circulate around it, and mix laterally into the Central Labrador Sea, where wintertime convection can occur to depths of 1 km. Deep convection in the Labrador Sea occurs in some winters but not others, affecting North Atlantic thermohaline circulation and hence our climate. In the project "VITALS" (Ventilation, Interactions and Transports Across the Labrador Sea), eddy exchanges will be observed using robotic gliders and profiling floats to determine connections to the Central Labrador Sea. This project will determine where, by what mechanisms, and how rapidly these exchanged waters mix.
We will monitor the production of fine scale (~5-50 m thick) layers of contrasting waters, and use profiler data to determine how rapidly the layers are mixed by turbulence. Fine-structure interleaving is a key link between lateral eddy exchanges and eventual turbulent dissipation (all lateral mixing must pass through fine structure before being mixed by turbulence); the "hot spots" identified will show us where the mixing is most intense, temporal variations will give clues about how the exchanges vary with time, and the overall mixing rates will be compared to the eddy exchange rates to determine the lateral fluxes of heat and other quantities. The vertical eddy diffusivities will be determined from fine scale current profiles measured by robotic floats and from lowered current profiler measurements.
This project hopes to connect the large (100 km) scale exchanges with the micro-scale (1 cm) mixing -- a range of seven decades!


Additional information:

The candidate should have a Physics or Math major or minor.



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