Development of eddies in an idealised shelf slope area due to an along slope barotropic jet

Measurements of the inflow of Atlantic Water to the Norwegian Sea show that a narrow jet forms along the shelf slope in the Svinøy and Ormen Lange areas west of mid Norway.The main density stratification can be divided into the warm Atlantic Water located on top and the colder and fresher Norwegian Sea Water masses below. The relatively thin interface is located at approximately 500–600 m depth. Eddies with periods between 20 and 80 h are found to develop in the flow of the Atlantic Water.In this paper a three-dimensional σσ-coordinate ocean model is used to study the formation of eddies in an idealised shelf area with a constant jet. Two numerical simulations are performed. The first simulation is barotropic, and the second is a two layer simulation with a barotropic jet. The numerical results show that eddies are generated by the inflowing jet in both simulations, but the eddies in the two layer simulation are weaker than in the barotropic simulation.The numerical results show that the length scale and the strength of the eddies depend on the stratification. For the barotropic case the growth rate agrees well with corresponding results from linear stability analysis. In the two layer simulation the jet loses the forced bell shape profile, the growth of the barotropic eddies is reduced, and an intensification occurs for the along shelf velocities in the interface.