An Idealised Model Study of Eddy Energetics in the Western Boundary 'Graveyard'

Yang, Zhibin, Zhai, Xiaoming, Marshall, David P. and Wang, Guihua (2021) An Idealised Model Study of Eddy Energetics in the Western Boundary 'Graveyard'. Journal of Physical Oceanography, 51 (4). 1265–1282. ISSN 0022-3670

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Abstract

Recent studies show that the western boundary acts as a ‘graveyard’ for westward-propagating ocean eddies. However, how the eddy energy incident on the western boundary is dissipated remains unclear. Here we investigate the energetics of eddy-western boundary interaction using an idealised MIT ocean circulation model with a spatially variable grid resolution. Four types of model experiments are conducted: (1) single eddy cases, (2) a sea of random eddies, (3) with a smooth topography and (4) with a rough topography. We find significant dissipation of incident eddy energy at the western boundary, regardless of whether the model topography at the western boundary is smooth or rough. However, in the presence of rough topography, not only the eddy energy dissipation rate is enhanced, but more importantly, the leading process for removing eddy energy in the model switches from bottom frictional drag as in the case of smooth topography to viscous dissipation in the ocean interior above the rough topography. Further analysis shows that the enhanced eddy energy dissipation in the experiment with rough topography is associated with greater anticyclonic-ageostrophic instability (AAI), possibly as a result of lee wave generation and non-propagating form drag effect.

Item Type: Article
Faculty \ School: Faculty of Science > School of Environmental Sciences
Depositing User: LivePure Connector
Date Deposited: 03 Feb 2021 00:59
Last Modified: 30 Sep 2021 16:11
URI: https://ueaeprints.uea.ac.uk/id/eprint/79143
DOI: 10.1175/JPO-D-19-0301.1

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