On the topographic modulation of large-scale eddying flows
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Authors
Radko, Timour
Kamenkovich, Igor
Subjects
Advisors
Date of Issue
2017-09
Date
Publisher
American Meteorological Society (AMS)
Language
Abstract
The modulation of large-scale eddying flows by gentle variation in topography is examined using a
combi- nation of direct numerical simulations and theoretical arguments. The basic state is represented by a laterally uniform zonal current that is restricted to the upper layer of a baroclinically unstable quasigeostrophic two-layer system. Therefore, the observed topographically induced generation of large-scale patterns is attributed entirely to the action of mesoscale eddies. The parameter regime investigated in this study is not conducive to the spontaneous formation of stationary zonal jets. The interaction between the large-scale current, eddies, and topography is described using an asymptotic multiscale model. The ability of the model to explicitly represent the interaction between distinct flow components makes it possible to unambiguously interpret the essential dynamics of the topographic/eddy-induced modulation. The multiscale solutions obtained reflect the balance between the modification of the meridional fluxes of potential vorticity (PV) due to the variation in topography and the corresponding modification of PV fluxes due to the induced large-scale circulation. The predictions of the asymptotic theory are successfully tested by comparing to the ones obtained by direct numerical simulations.
Type
Article
Description
The article of record as published may be found at http://dx.doi.org/10.1175/JPO-D-17-0024.1
Series/Report No
Department
Oceanography
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
National Science Foundation (NSF)
Funding
Grant OCE-1155866 (NSF)
Grant OCE-1154923 (NSF)
Grant OCE-1154923 (NSF)
Format
16 p.
Citation
T. Radko, I. Kamenkovich, "On the topographic modulation of large-scale eddying flows," Journal of Physical Oceanography, v.47, (September 2017), pp. 2157-2172.
Distribution Statement
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.