| Summary: | Sea level and current observations made over the Oregon
continental shelf exhibit wavelike characteristics in a frequency band
from approximately 0.15 to 0.45 cpd. In a narrow band around
0.22 cpd the current-sea level relationship is consistent with the
predicted values for the first mode of Robinson's continental shelf
waves. In addition, an interesting relationship exists between the
form of the sea level-current coherency spectra and the arrangement
of the maximum frequencies for the first three shelf wave modes.
The currents were measured in 100 m of water about seven
nautical miles off Depoe Bay, Oregon. Current meters were placed
at 25, 50 and 75 m depth. The duration of the experiment was from
18 April 1968 until 11 September 1968. Due to some instrument failures
a complete current data set for this period was not obtained.
Simultaneous and continuous measurements of surface elevation and
atmospheric pressure were also obtained at Newport, Oregon, a
nearby coastal station.
Shelf wave dispersion curves and eigenfunctions for the Oregon
coastal profile are computed using a new numerical technique. These
are compared with a low frequency (about 0.03 cpd to 0.75 cpd)
spectral analysis of the current, sea level and atmospheric pressure
records.
The relative vertical uniformity of the currents, as a function of
frequency, is examined. The longshore component of the current
appears to be substantially more barotropic than the onshore-offshore
component. === Graduation date: 1972
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