Formation and maintenance of shelfbreak fronts in an unstratified flow

Abstract

Examines the three-dimensional nature of the passive tracer front proposed by Chapman who used a depth averaged model with no density variations. Uses a three-dimensional primitive equation model in which the bottom boundary layer is explicitly resolved, finite vertical viscisity and diffusivity included but stratification excluded. Outlines the depth averaged model procedures as well as describing the three-dimensional model. Comparison of results from both models indicates differences for 1) rate of decrease of the alongshelf velocity, 2) cross shelf velocity structure (and transport at shelf break). Consideration of Lagrangian flow and deep ocean inflow shows that the horizontal shear at the shelf break does not act as a barrier to the neutrally buoyant particles near the bottom. A deep ocean inflow actually appears to increase offshore flow in the bottom boundary layer. Notes that stratification may qualitatively change results. (C.J.U.)