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Small‐scale topographic form stress and local dynamics of the Southern Ocean
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Abstract
The contribution of small‐scale abyssal hill topography to the topographic form stress and local dynamics of the Southern Ocean is investigated using a high‐resolution model of the sector of the Southern Ocean south of Tasmania and New Zealand. The results of two simulations, with and without small, O(1–100 km), scale topography, confirm that the effects of small‐scale topography are exerted through the generation of strong topographic form stress leading to transient eddy dissipation and changes in flow meanders. Small‐scale topographic form stress is comparable in magnitude to that generated by large‐scale topography, but with a pairwise distribution of positive and negative stress values upstream and downstream of the Macquarie Ridge, consistent with the meandering of the flow. In the experiment without small‐scale topography, the bottom mean flow speed increases, while the surface mean speed slightly decreases, making the mean flow more barotropic. Eddy kinetic energy also greatly enhances throughout the water column after removing small‐scale topography. Our results suggest that small‐scale topography has strong impact on transient eddies and plays an important role for setting the vertical structure of the flow and the equilibration and position of flow meanders.
Item Type: | Article |
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Authors/Creators: | Zhang, X and Nikurashin, M |
Keywords: | ocean topography, abyssal hills, Southern Ocean, fronts, topographic form stress |
Journal or Publication Title: | Journal of Geophysical Research: Oceans |
Publisher: | Wiley-Blackwell Publishing Inc. |
ISSN: | 2169-9275 |
DOI / ID Number: | 10.1029/2019JC015420 |
Copyright Information: | Copyright 2020 American Geophysical Union. |
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Item Statistics: | View statistics for this item |
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