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Topographical Control of the Source-Sink and Wind Stress-Driven Planetary Geostrophic Circulation in a Polar Basin

Lookup NU author(s): Estanislao Gavilan Pascual-Ahuir, Professor Andrew Willmott, Dr Miguel Morales Maqueda

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This is the final published version of an article that has been published in its final definitive form by Wiley-Blackwell, 2020.

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Abstract

© 2020. American Geophysical Union. All Rights Reserved. The effects of topography on the barotropic circulation in a polar basin are examined analytically and numerically. New approximate linear analytical solutions are presented for steady-state wind and boundary forced barotropic planetary geostrophic circulation in a circular polar basin with a step shelf. The solutions are obtained by retaining the full spherical geometry in the derivation of the forced potential vorticity equation; thereafter the colatitude is fixed in the coefficients of this governing equation. The accuracy of the analytical solutions is evaluated by comparing them with the equivalent numerical solutions obtained using the NEMO modeling system. Subsequently, the impact of a nonuniform width shelf on source-sink-driven circulation is investigated numerically. The equipartition of fluid entering the source strait into cyclonic and anticyclonic shelf currents, exiting the basin at the sink strait, in a basin with a uniform width shelf is shown to be modified when the shelf width varies. In general, the wider shelf supports a current with larger transport, irrespective of the azimuthal extent of the wider shelf. The study concludes with a numerical investigation of wind-driven circulation in a basin with a step shelf, three straits, and a transpolar ridge, a prototype Arctic Ocean simulation. Topographic steering by the ridge supports a transpolar drift current, the magnitude of which depends on the ridge height. Without the ridge, the transpolar drift current is absent and the circulation is confined to gyres on the shelf and in the deep basin.


Publication metadata

Author(s): Gavilan Pascual-Ahuir E, Willmott AJ, Morales Maqueda M, Luneva M

Publication type: Article

Publication status: Published

Journal: Journal of Geophysical Research: Oceans

Year: 2020

Volume: 125

Issue: 3

Print publication date: 24/03/2020

Online publication date: 10/03/2020

Acceptance date: 07/03/2020

Date deposited: 06/04/2020

ISSN (print): 2169-9275

ISSN (electronic): 2169-9291

Publisher: Wiley-Blackwell

URL: https://doi.org/10.1029/2019JC015571

DOI: 10.1029/2019JC015571


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