Dynamics of circulation off the west coast of Vancouver Island

Abstract

The Princeton Ocean Model (Blumberg and Mellor,1987) is used to examine dynamical balances in the summer and winter three-dimensional circulation along the west coast of Vancouver Island. The model is initialized with horizontally averaged temperature and salinity over a domain 445 km alongshore by 145 km cross-shore. Forcing is by uniform summer and winter winds and by discharge from Juan de Fuca Strait. A topographic stress parameterization (Eby and Holloway, 1994) is included. In the absence of topographic stress and Juan de Fuca discharge, wind-forced summer circulation is dominated by equatorward flow over the shelf and slope. With topographic stress included, poleward coastal flow develops over the shelf and shelfbreak with a transition zone between poleward and equatorward flow over the slope. When the buoyancy forcing is introduced, an eddy is developed off the mouth of the Juan de Fuca Strait. Winter circulation tends to be poleward for all combinations of wind, buoyancy and topographic stress forcings. These results agree qualitatively with observations.