Record Details
On coastal trapped waves at low latitudes in a stratified ocean
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | On coastal trapped waves at low latitudes in a stratified ocean |
| Names |
Romea, Richard Dennis
(creator) Allen, John S. (advisor) Smith, Robert L. (advisor) |
| Date Issued | 1982-06-10 (iso8601) |
| Note | Graduation date: 1983 |
| Abstract | The response on the continental shelf of a baroclinic ocean to driving by an alongshore coastal wind stress and by barotropic and baroclinic wind forced interior motions is studied as a function of latitude. The relative excitation of continental shelf waves and internal Kelvin waves is studied. The response of a rotating stratified ocean with a vertical boundary, forced at the surface by an alongshore coastal wind stress, shows vertically propagating subinertial motions. Several examples which illustrate the basic properties of the response are presented. Changes in amplitude and frequency with depth are predicted. Components that decay with depth from the surface and components that represent coastal internal Kelvin waves with negative vertical group velocity and upward phase propagation are forced. The effect of bottom Ekman layer friction and slope topography on free internal Kelvin waves is examined, using both a steep and weak slope model. The steep slope represents the low latitude case while the weak slope represents the mid-latitude case. There are substantial differences between the results from the two models. Free waves are frictionally damped and offshore and vertical phase shifts are induced by friction, as well as an onshore flow. Topography induces changes to the wave frequency and alongshore phase speed. The modal amplitude is altered and an onshore flow is induced. Sea level and current velocity data from the equator to 17°S on the west coast of South America show that low frequency (0.1-0.2 cpd) fluctuations propagate poleward with phase speeds similar to those predicted for first mode baroclinic Kelvin waves. The sea level and currents are coherent and approximately 1800 out of phase. The waves do not appear to be the result of local atmospheric forcing. Empirical orthogonal functions show that the alongshore and vertical structure of alongshore velocity is consistent with first mode internal Kelvin waves. |
| Genre | Thesis/Dissertation |
| Topic | Ocean waves |
| Identifier | http://hdl.handle.net/1957/27929 |
