A numerical study on the influence of the Mid-Atlantic Ridge on nonlinear first-mode baroclinic Rossby waves generated by seasonal winds.

Abstract

Investigates numerically the propagation across the North Atlantic of the first mode baroclinic Rossby waves generated at the eastern boundary by a wind forcing obtained from real wind data. The model ocean is two layer with a rigid top and variable bottom topography. The model ridge compromises a realistic representation of the mid Atlantic ridge and the quasi geostrophic approximation. The sponge layers are designed with an enhanced barotropic friction that rapidly damps the fluid motions. The model is forced by purely fluctuating wind stress curl (EOF analysis of FGGE wind data). The flat bottom baroclinic response consists of coastally forced and free annual period baroclinic Rossby waves. Free waves of small amplitude are found at the middle of the basin. As in the mid ridge experiment the eastern bondary is a source of the baroclinic waves. The ridge appears to a source of waves that could contribute to the boundary transport as well as being a barrier to westward travelling energy.