On Eddy–Topographic Stress Representation

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  • 1 Institute of Ocean Sciences, Sidney, British Columbia, Canada
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Abstract

A parameterization of eddy–topographic stress interactions has been proposed previously by Holloway, based on the statistical mechanical equilibria of unforced inviscid models. Tendency toward such equilibria may account for the presence of deep currents observed along oceanic continental margins. The parameterization includes simplifications of the statistical equilibria permitting a local implementation of these tendencies into coarse-resolution ocean models. The approximations involved in this parameterization are examined in simulations with an inviscid quasigeostrophic model with idealized topography representing a continental margin. Time-averaged flows are in qualitative agreement with the suggested pattern and are dominated by a large-scale cyclonic circulation along the basin margin. Results show that the parameterized equilibria can significantly overestimate the along-isobath transport due to neglect of the relative vorticity component of the potential vorticity.

Abstract

A parameterization of eddy–topographic stress interactions has been proposed previously by Holloway, based on the statistical mechanical equilibria of unforced inviscid models. Tendency toward such equilibria may account for the presence of deep currents observed along oceanic continental margins. The parameterization includes simplifications of the statistical equilibria permitting a local implementation of these tendencies into coarse-resolution ocean models. The approximations involved in this parameterization are examined in simulations with an inviscid quasigeostrophic model with idealized topography representing a continental margin. Time-averaged flows are in qualitative agreement with the suggested pattern and are dominated by a large-scale cyclonic circulation along the basin margin. Results show that the parameterized equilibria can significantly overestimate the along-isobath transport due to neglect of the relative vorticity component of the potential vorticity.

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