Dynamics of Tidally Forced Basin-wide Coastal Eddies

The dynamics generating and governing tidally induced meso-scale recirculations in wide coastal sea straits are investigated using the TIDAL STRESS formulation. In this formulation we introduce the Stokes’ drift into the residual dynamics and present the Lagrangian Tidal Stress estimate in terms of quasi-Eulerian fields.

An analysis is presented of these processes active within Dixon Entrance and Hecate Strait off the west coast of Canada using idealized tidal and geomorphological representations. It is shown that the generation of an observed cyclonic basin-wide eddy in eastern Dixon Entrance is consistent with a tidal rectification process active over the strongly sloping escarpment connecting Dixon Entrance and Hecate Strait.

It is concluded that a sufficiently strong rectification process active over a limited sector of the eddy circumference may substantially influence the circulation within adjacent bodies of water where perhaps no significant tidal nonlinearities operate.