Record Details
The response of Oregon shelf waters to wind fluctuations : differences and the transition between winter and summer
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | The response of Oregon shelf waters to wind fluctuations : differences and the transition between winter and summer |
| Names |
Sobey, Edwin J. C., 1948-
(creator) Smith, Robert L. (advisor) |
| Date Issued | 1977-02-15 (iso8601) |
| Note | Graduation date: 1977 |
| Abstract | The physical characteristics of continental shelf waters off Oregon during late winter and spring of 1975 are described and compared with observations taken previously during summer. The currents in winter are barotropic in the monthly means while in summer the currents are baroclinic. Alongshore current fluctuations on the time scale of a few days are depth dependent in winter but become depth independent in summer. The current shear changes sign on the several day time scale in winter while in summer the deeper currents are always northward with respect to the near surface currents. Alongshore coherences of sea level and currents indicate that winter fluctuations generally propagate southward rather than northward as previously observed in summer. These winter fluctuations in alongshore currents also have onshore/offshore phase speeds that are comparable in magnitude to their alongshore phase speeds. There is no evidence for free continental shelf wave activity in winter although forced waves (travelling predominately southward, as do the meteorological disturbances) may exist. The Gill and Schumann (1974) model, which predicts sea level from a knowledge of the alongshore components of winds along the coastline, is tested for winter and summer in 1975 and found to have some predictive ability for fluctuations on the time scale of several days. The transition from winter to summer is initiated in a dramatic barotropic event and continues as a longer period baroclinic adjustment. The former is marked by a sudden reversal of currents and a lowering of sea level while the latter is marked by a slow rising of the pycnocline and with it the layer of maximum vertical shear. Both the barotropic changes at the transition event and the adjustment of the density field, which occurs after the transition event, are directly forced by the local wind. |
| Genre | Thesis/Dissertation |
| Topic | Ocean currents -- North Pacific Ocean |
| Identifier | http://hdl.handle.net/1957/27739 |
