Oregon State University
Cornejo-Rodriguez, M. Pilar.
Propagation and forcing of high frequency sea level variability in the eastern equatorial Pacific.
Degree: MS, Oceanography, 1987, Oregon State University
Sea level and wind data from coastal and island stations from
Buenaventura, Colombia (4°N) to Callao, Peru (12°S) have been
analyzed for the 1979-1984 time period, to describe the seasonal and
interannual variations in the characteristics of short time scale
variability (1-2 weeks). Auto- and cross spectral analyses are used
to make comparisons between Austral summers and winters as well as
interannual comparisons between the 1982-1983 El Nino/Southern
Oscillation (ENSO) period and non-ENSO years. The principal results
show weak evidence of local forcing of the sea level by the
alongshore wind during the whole year without significant
differences between summer and winter seasons. The alongshore
coherence and phase spectra between the sea level series show
evidence of poleward propagating fluctuations at speeds of 2.6-3.0
ms^-1 during winter, but no propagation is evident during summer.
There is also a large energy increase in coastal sea level,
especially in the 8-11 day band, during the 1982-1983 ENSO episode.
This increase is associated with a non-dispersive, poleward
propagation of events at speeds of 3.11-3.6 ms^-1. The propagating
fluctuations are superimposed on a weak, locally forced variability.
The only plausible source for the observed coastal fluctuations
appears to be trapped waves in the equatorial waveguide. Additional
equatorial data from subsurface pressure gauges in the Galapagos
Islands and inverted echo sounders at 3°N,95°W, 3°N,85°W and
2°S,85°W are used to explore the possibility that the coastal signal
during the 1982-1983 ENSO episode is connected to the arrival of
energy in the form of equatorially trapped Rossby-gravity (Yanai)
and Kelvin waves, and to determine the respective contributions of
the two wave types. Cross spectral analyses, frequency domain EOF
analysis and the characteristics of equatorial waves demonstrate
that equatorially trapped Yanai waves are the principal source of
the propagating signals in the coastal sea levels during the
1982-1983 ENSO. During the 1982-1983 ENSO, between 64% and 91% of
the coastal SLH variability in the 8-11 day period band is
associated with antisymmetric variability across the equator. Phase
in this band is zonally invariant along the equator but is poleward
propagating along the coast, consistent with the conversion of
stationary, equatorial lanai waves into coastal trapped waves.
Advisors/Committee Members: Enfield, David B. (advisor).
Subjects/Keywords: Sea level – Pacific Coast (Peru)
to Zotero / EndNote / Reference
APA (6th Edition):
Cornejo-Rodriguez, M. P. (1987). Propagation and forcing of high frequency sea level variability in the eastern equatorial Pacific. (Masters Thesis). Oregon State University. Retrieved from http://hdl.handle.net/1957/23601
Chicago Manual of Style (16th Edition):
Cornejo-Rodriguez, M Pilar. “Propagation and forcing of high frequency sea level variability in the eastern equatorial Pacific.” 1987. Masters Thesis, Oregon State University. Accessed September 19, 2019.
MLA Handbook (7th Edition):
Cornejo-Rodriguez, M Pilar. “Propagation and forcing of high frequency sea level variability in the eastern equatorial Pacific.” 1987. Web. 19 Sep 2019.
Cornejo-Rodriguez MP. Propagation and forcing of high frequency sea level variability in the eastern equatorial Pacific. [Internet] [Masters thesis]. Oregon State University; 1987. [cited 2019 Sep 19].
Available from: http://hdl.handle.net/1957/23601.
Council of Science Editors:
Cornejo-Rodriguez MP. Propagation and forcing of high frequency sea level variability in the eastern equatorial Pacific. [Masters Thesis]. Oregon State University; 1987. Available from: http://hdl.handle.net/1957/23601