A model of secondary upwelling over the shelf break

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Abstract
In this unsteady barotropic model of the circulation over an oceanic continental shelf, account is taken of the shelf break by introducing a leaky boundary condition at the edge of the shelf which allows a weak linkage between the rapidly changing flow on the shelf and the more slowly varying deep water flow offshore of the shelf break. The scaled gradients of the bottom topography offshore and onshore of the break are α L and α R respectively. It is found that the amount of shelf break upwelling ranges from zero when α L = α R and the break is absent, through intermediate values when α L is moderately greater than α R and transport leaks off the shelf into the deep ocean, to a maximum as α L a maximum as α L → ∞ and the shelf break effectively acts as a barrier between the shelf circulation and the deep water circulation. As the sharpness of the shelf break increases then a stronger current develops along the edge of the shelf.