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.
Funding
Australian Research Council
History
Publication title
Journal of Geophysical Research: Oceans
Volume
125
Issue
8
Article number
e2019JC015420
Number
e2019JC015420
Pagination
1-18
ISSN
2169-9275
Department/School
Institute for Marine and Antarctic Studies
Publisher
Wiley-Blackwell Publishing Inc.
Place of publication
United States
Rights statement
Copyright 2020 American Geophysical Union.
Repository Status
Restricted
Socio-economic Objectives
Measurement and assessment of marine water quality and condition; Climate change models