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dc.contributor.authorBarth, John A.  Concept link
dc.date.accessioned2011-12-27T16:23:05Z
dc.date.available2011-12-27T16:23:05Z
dc.date.issued1987-10
dc.identifier.urihttps://hdl.handle.net/1912/4955
dc.descriptionSubmitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution October 1987en_US
dc.description.abstractA two-layer shallow water equation model is used to investigate the linear stability of a coastal upwelling front. The model features a surface front near a coastal boundary and bottom topography which is an arbitrary function of the cross-shelf coordinate. By combining the various conservation statements for the global properties of the system, a general stability theorem is established which allows the a priori determination of the stability of a coastal upwelling front. Unstable waves are found for the modelled coastal upwelling front. The unstable wave motions are frontally-trapped and dominant in the upper layer. The wave propagates phase in the direction of the basic state flow and the primary energy conversion is via baroclinic instability. The effect of varying the model parameters is presented. Moving the front closer than ~ 2 Rossby radii to the coastal boundary results in a decrease in the growth rate of the fastest growing wave. Increasing the overall vertical shear of the basic state flow, by either decreasing the lower layer depth or increasing the steepness of the interface, results in an increase in the growth of the fastest growing wave. A bottom sloping in the same sense as the interface results in a decrease of the growth rates and alongfront wavenumbers of the unstable waves in the system. Linearized bottom friction is included in the stability model and results in a decrease in the growth rates of the unstable waves by extracting energy from the system. Since the unstable mode is strongest in the upper layer, bottom friction will not stabilize the upwelling front. A comparison between the predictions from the simple two-layer model and observed alongfront variability for three areas of active upwelling is presented. Reasonable agreement is found, suggesting that observed alongfront variability can be interpreted in terms of the instability of a coastal upwelling front.en_US
dc.description.sponsorshipThis study was supported by the National Science Foundation Grant OCE 84-08563 and the Office of Naval Research Coastal Ocean Sciences Program 10/1984.37.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherMassachusetts Institute of Technology and Woods Hole Oceanographic Institutionen_US
dc.relation.ispartofseriesWHOI Thesesen_US
dc.subjectUpwellingen_US
dc.subjectWavesen_US
dc.titleStability of a coastal upwelling front over topographyen_US
dc.typeThesisen_US
dc.identifier.doi10.1575/1912/4955


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