Some aspects of the barotropic instability of continental boundary currents are investigated herein. In the first problem, a piecewise linear wall-jet is perturbed by the most unstable linear mode and the nonlinear evolution of the disturbance is computed. It is shown that the eddies in the wall-jet case evolve much differently than those resulting from the instability of a free jet. This simple model illustrates that even without dissipative processes, a rapid diffusion of mean momentum and vorticity occurs. This contrasts with the main result of this study presented in the second problem where it is argued that the use of a classical eddy parametrization in the analysis of continental boundary currents leading to the diffusion of momentum and relative vorticity fails to recognize that the relevant eddies are dominated by the conservation of potential vorticity, which in turn may produce an increase in the mean relative vorticity. To illustrate this effect, we examine a non-inflected barotropic shear flow destabilized by the cross stream variation in the bottom topography of a continental slope. The finite amplitude evolution of the waves is analyzed in a simple model with a steplike bottom topography and with piecewise uniform potential vorticity distribution. The increase in maximum mean vorticity is computed for various values of the Rossby number and the topographic elevation, and it is suggested that a similar effect, taking into account the isopycnal topography as well as the isobaths, could maintain the large inshore shear of the Gulf Stream. Cross shelf transport of different water types (i.e.: potential vorticity and passive tracers) are also computed and suggested to be pertinent to the more realistic oceanic problem involving baroclinic effects. The numerical calculation employs the well known method of contour dynamics, and the Green's function appropriate for the step-like topography is derived. / Source: Dissertation Abstracts International, Volume: 54-07, Section: B, page: 3531. / Major Professor: Melvin E. Stern. / Thesis (Ph.D.)--The Florida State University, 1993.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_76974 |
| Contributors | Bidlot, Jean Raymond., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 120 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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