The adjustment of barotropic currents at the shelf break to a sharp bend in the shelf topography
Citable URI
https://hdl.handle.net/1912/5674Location
Georges BankDOI
10.1575/1912/5674Keyword
Ocean currentsAbstract
During January-March, Scotian Shelf water has been observed to flow episodically
from the southwestern Scotian Shelf directly across the Northeast Channel to Georges
Bank. The possible factors that allow Scotian Shelf water to break the topographic
constraint presented by the Northeast Channel and flow directly to Georges Bank are
considered. As a simple analog to the flow over the southwestern Scotian Shelf near
the Northeast Channel, the adjustment of a barotropic current near a shelf-break to
a sharp bend in the shelf topography is studied numerically. For parameters within
the oceanographic range, the adjustment to the bend is smooth and steady with no
eddies shed at the corner. The vorticity dynamics allow a balance between the vortex
stretching in the flow and the curvature in the flow. This is possible since the bend is a
right-hand one facing downstream, a similar balance not being possible for a left-hand
bend, in which case eddy formation is likely. A simple model of this balance clarifies
the vorticity dynamics and provides the scaling rc = √eL/0.765 for any streamline in
the flow, where rc is the radius of curvature at the corner, E = u0/fL and L = h0/b,
where uo is the initial speed, f the coriolis parameter, h0 the initial depth and b
the bottom slope. These results show that other factors such as stratification, wind
stress, and time-dependent inflow must play a role in any flow across the Northeast
Channel.
Description
Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 1996
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Suggested Citation
Thesis: Williams, William J., "The adjustment of barotropic currents at the shelf break to a sharp bend in the shelf topography", 1996-02, DOI:10.1575/1912/5674, https://hdl.handle.net/1912/5674Related items
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