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dc.contributor.authorHristova, Hristina G.  Concept link
dc.contributor.authorDijkstra, Henk A.  Concept link
dc.contributor.authorSpall, Michael A.  Concept link
dc.date.accessioned2011-02-22T19:33:43Z
dc.date.available2011-02-22T19:33:43Z
dc.date.issued2010-03-01
dc.identifier.citationJournal of Marine Research 68 (2010): 215-236en_US
dc.identifier.urihttps://hdl.handle.net/1912/4348
dc.descriptionAuthor Posting. © Sears Foundation for Marine Research, 2010. This article is posted here by permission of Sears Foundation for Marine Research for personal use, not for redistribution. The definitive version was published in Journal of Marine Research 68 (2010): 215-236, doi:10.1357/002224010793721424.en_US
dc.description.abstractUsing a fully-implicit high-resolution two-layer quasi-geostrophic model combined with pseudo-arclength continuation methods, we perform a bifurcation analysis of double-gyre ocean flows to study their initial oscillatory instabilities. In this model, both wind- and thermally-forced flows can be represented. We demonstrate that on the branch of anti-symmetric steady-state solutions the ratio, Ω, of the flow advective speed to the long internal Rossby wave speed determines the type of oscillatory modes to first become unstable. This is the same nondimensional parameter that controls the shape of the geostrophic contours in the linear limit of the circulation. For large values of Ω, the first Hopf bifurcations correspond to the classical baroclinic modes with inter-monthly time periods arising from shear instability of the flow. For small values of Ω, the first Hopf bifurcations correspond instead to barotropic Rossby modes with shorter, monthly periods arising from mixed barotropic-baroclinic instability of the flow. By considering both a wind-forced and a thermally-forced ocean, we show that this is a robust feature that does not depend on the type of forcing driving the circulation.en_US
dc.description.sponsorshipNSF Grant OCE-0423975, NSF Grants OCE-042975 and OCE-0850416en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherSears Foundation for Marine Researchen_US
dc.relation.urihttps://doi.org/10.1357/002224010793721424
dc.titleOnset of time-dependence in a double-gyre circulation : barotropic basin modes versus classical baroclinic modesen_US
dc.typeArticleen_US
dc.identifier.doi10.1357/002224010793721424


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