Time-dependent response to cooling in a beta-plane basin

dc.contributor.author Pedlosky, Joseph
dc.date.accessioned 2010-12-14T16:09:13Z
dc.date.available 2010-12-14T16:09:13Z
dc.date.issued 2006-11
dc.description Author Posting. © American Meteorological Society, 2006. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 36 (2006): 2185-2198, doi:10.1175/JPO2967.1. en_US
dc.description.abstract The time-dependent response of an ocean basin to the imposition of cooling (or heating) is examined in the context of a quasigeostrophic, two-layer model on the beta plane. The focus is on the structure and magnitude of the vertical motion and its response to both a switch-on forcing and a periodic forcing. The model employed is a time-dependent version of an earlier model used to discuss the intensification of sinking in the region of the western boundary current. The height of the interface of the two-layer model serves as an analog of temperature, and the vertical velocity at the interface consists of a cross-isopycnal velocity modeled in terms of a relaxation to a prescribed interface height, an adiabatic representation of eddy thickness fluxes parameterized as lateral diffusion of thickness, and the local vertical motion of the interface itself. The presence of time dependence adds additional dynamical features to the problem, in particular the emergence of low-frequency, weakly damped Rossby basin modes. If the buoyancy forcing is zonally uniform the basin responds to a switch-on of the forcing by coming into steady-state equilibrium after the passage of a single baroclinic Rossby wave. If the forcing is nonuniform in the zonal direction, a sequence of Rossby basin modes is excited and their decay is required before the basin achieves a steady state. For reasonable parameter values the boundary layers, in which both horizontal and vertical circulations are closed, are quasi-steady and respond to the instantaneous state of the interior. As in the steady problem the flow is sensitive to small nonquasigeostrophic mass fluxes across the perimeter of the basin. These fluxes generally excite basin modes as well. The basin modes will also be weakly excited if the beta-plane approximation is relaxed. The response to periodic forcing is also examined, and the sensitivity of the response to the structure of the forcing is similar to the switch-on problem. en_US
dc.description.sponsorship This research was supported in part by NSF Grant OCE-9901654, en_US
dc.format.mimetype application/pdf
dc.identifier.citation Journal of Physical Oceanography 36 (2006): 2185-2198 en_US
dc.identifier.doi 10.1175/JPO2967.1
dc.identifier.uri https://hdl.handle.net/1912/4226
dc.language.iso en_US en_US
dc.publisher American Meteorological Society en_US
dc.relation.uri https://doi.org/10.1175/JPO2967.1
dc.subject Vertical motion en_US
dc.subject Ocean dynamics en_US
dc.subject Buoyancy en_US
dc.subject Ocean models en_US
dc.title Time-dependent response to cooling in a beta-plane basin en_US
dc.type Article en_US
dspace.entity.type Publication
relation.isAuthorOfPublication f5dbc523-4176-4180-9ef3-b4f6dbff4163
relation.isAuthorOfPublication.latestForDiscovery f5dbc523-4176-4180-9ef3-b4f6dbff4163
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