Influences of a rough bottom topography on flow kinematics in an eddy-resolving circulation model.

Abstract

Investigates the effects of a rough topography in a primitive equation eddy resolving circulation model of an idealized ocean basin. The experiment is based on the multilevel model of Bryan, the model being driven by steady wind and thermal forcing. The interactions of the deep current fluctuations with the synoptic scale irregularities of the ocean floor enhance the baroclinicity of the eddy field. Topographic effects are associated with a substantial decrease of eddy kinetic energy below the thermocline and a much more depth dependent structure, especially in areas of weaker flow intensity. Bottom topography appears to stabilize (anticyclonic) eddies, giving lifetimes of more than 11/2 years. Quasi geostrophic theory might therefore not be applicable. Particle dispersion becomes almost isotropic below the thermocline, in the upper layers a preference for zonal diffusivity remains.