Numerical models using one- and two-layer generalized geostrophic equations are developed and applied to the study of geostrophic turbulence. The classical results of geostrophic turbulence are extended by freeing the experiments from the restriction of weak vertical displacements, thereby allowing finite-amplitude, frontal effects. / Turbulence experiments with the one-layer model reveal an attracting length scale, which depends on the energy level. When the frontal effects are present, anticyclones merge into a few, coherent, large, and long-lived eddies, while cyclones shatter and form a small-scale, quasi-geostrophic background. / Experiments with the two-layer model indicate that a distinction exists between geostrophic turbulence at high and low energy levels. At high energy levels, when frontal effects are present and when the traditional quasi-geostrophic model is invalid, large, coherent anticyclones emerge from motions at scales less than the deformation radius; these are robust and retain their potential energy against the destructive action of baroclinic instability. This is an important new result, because so far, with only quasi-geostrophic models in use, it has long been thought that such eddies were unstable. Experiments with isolated eddies of varying sizes and amplitudes, with variable strength of the $\beta$ effect and with variable depth of the lower layer reveal that, at the finite amplitudes, anticyclones are far more stable than cyclones, and that strong anticyclones are more stable than weak eddies of either polarity. Eddies are also stable as the lower layer is deepened. The $\beta$-effect is destablizing when the lower layer is infinitely deep, and is stabilizing when the lower layer has a finite depth. / Source: Dissertation Abstracts International, Volume: 51-01, Section: B, page: 0370. / Major Professor: Benoit Cushman-Roisin. / Thesis (Ph.D.)--The Florida State University, 1989.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_78161 |
| Contributors | Tang, Benyang., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 121 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
Page generated in 0.0017 seconds