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Small-scale topographic form stress and local dynamics of the Southern Ocean


Zhang, X and Nikurashin, M, Small-scale topographic form stress and local dynamics of the Southern Ocean, Journal of Geophysical Research: Oceans, 125, (8) Article e2019JC015420. ISSN 2169-9275 (2020) [Refereed Article]


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Copyright 2020 American Geophysical Union.

DOI: doi:10.1029/2019JC015420


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(1100 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 Details

Item Type:Refereed Article
Keywords:ocean topography, abyssal hills, Southern Ocean, fronts, topographic form stress
Research Division:Engineering
Research Group:Fluid mechanics and thermal engineering
Research Field:Geophysical and environmental fluid flows
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Measurement and assessment of marine water quality and condition
UTAS Author:Zhang, X (Ms Xihan Zhang)
UTAS Author:Nikurashin, M (Dr Maxim Nikurashin)
ID Code:140229
Year Published:2020
Funding Support:Australian Research Council (DP170102162)
Deposited By:Oceans and Cryosphere
Deposited On:2020-08-03
Last Modified:2021-04-28
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