Inertia-Gravity Wave Generation from Unsteady Ocean Currents

Northwest Research Associates, Incorporated, Seattle WA

Investigators

Abstract

0137533/Lelong This project uses direct numerical simulation to look at the effectiveness of internal gravity wave radiation from rapidly varying almost geostrophic currents. The primary scientific motivation is to determine to what degree such a process could explain the background level of internal wave radiation in the ocean, away from boundaries. The work is guided both by observations of high internal wave energy near oceanic fronts and by numerical studies of the radiation of gravity waves during the life cycle of baroclinic eddies in the atmosphere. The approach consists of using two types of numerical models, a hydrostatic isopycnal model (HIM) and a non-hydrostatic Navier-Stokes solver (S-FIT), at high spatial resolution to examine the nonlinear evolution of instabilities on a baroclinic jet. The project includes the use of a novel diagnostic tool for separating the internal wave component. A balanced model will be used to invert the potential vorticity field. The resulting balanced vortical flow will then be subtracted from the full flow.