|
A continously stratified, two-dimensional (vertical and seaward) model is used to study the effects of alongshore wind on a front between lighter water over the continental shelf and heavier water in the offshore ocean. The model produces three components of alongshore flows: one component associated with the horizontal density front and two wind-driven components, one near the coast and one over the shelf break. The cross-shore circulation has two near-surface features; a seaward component resulting from the offshore density gradient and a shoreward (seaward) component resulting from the right-hand (left-hand) alongshore wind stress, which has the coast to the right (left), faceing downstream. These two components contribute to the maintenance of the front. With no wind, low-density water over the shelf tends to move toward the offshore ocean associated with the near-surface seaward flow, resulting in flatter isopycnal surfaces. A moderate right-hand alongshore wind suppresses the density-driven surface flow and constrains the shelf water, while a strong wind in the same direction pushes the front shoreward and makes isopycnal surfaces steeper, resulting in increased exchange of the shelf water. A left-hand alongshore wind contributes to more rapid frontal relaxation an a seaward shift in its position. These results are applied to the Labrador Shelf. |