eprintid: 1446863
rev_number: 9
eprint_status: archive
userid: 636
dir: disk0/01/44/68/63
datestamp: 2017-09-12 14:41:47
lastmod: 2017-09-12 14:41:47
status_changed: 2017-09-12 14:41:47
type: thesis
metadata_visibility: show
item_issues_count: 0
creators_name: White, Andrew James
title: Analytic techniques for short-term ocean current forecasting
ispublished: unpub
divisions: F59
note: Thesis digitised by ProQuest.
abstract: This thesis concerns the motion of oceanic vortices and comprises two parts. Part I examines the dynamics of point vortices in a two-layer fluid near large amplitude, sharply varying topography, e.g. continental shelf regions. Topography takes the form of an infinitely long step change in depth and the two-layer stratification is chosen such that the height of topography in the upper layer is a small fraction of the overall depth, enabling quasi-geostrophic theory to be used in both layers even though the topography is large amplitude. An analytic expression for the dispersion relation of free topographic waves in this system is found. Weak lower-layer vortices are studied using linear theory and, depending on their sign, are able to produce significant topographic wave radiation in their wakes. Upper-layer vortices produce relatively small amplitude topographic wave radiation. Contour dynamics results are used to investigate the nonlinear regions of parameter space. For lower-layer vortices linear theory is a good approximation, but for upper-layer vortices complicated features evolve and linear theory is only valid for weak vortices. The motion of hetons (two vortices, one in each layer) and dipoles are also studied. Part II involves the investigation and prediction of the motion of Loop Current Eddies (LCE's) in the Gulf of Mexico. By incorporating the major features of LCE's into a simple eddy model it is attempted to discover if it is possible to deduce the characteristics of a distant eddy from a set of measured velocities at a fixed location and further, predict the subsequent motion of the eddy. First, a circular model for the eddy shape is adopted and the Helmholtz equation is solved in the far-field. Second, a more sophisticated, precessing, elliptical model is developed, the solution involving Mathieu functions. In both cases comparison with actual current meter data is used to demonstrate the validity of the models.
date: 2005-02-28
id_number: PQ ETD:602805
oa_status: green
full_text_type: other
thesis_class: doctoral_open
language: eng
thesis_view: UCL_Thesis
primo: open
primo_central: open_green
verified: verified_manual
full_text_status: public
pages: 208
institution: UCL (University College London)
department: Department of Mathematics
thesis_type: Doctoral
citation:        White, Andrew James;      (2005)    Analytic techniques for short-term ocean current forecasting.                   Doctoral thesis , UCL (University College London).     Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/1446863/1/White.Andrew.James_thesis.pdf