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Antarctic Circumpolar Current transport and barotropic transition at Macquarie Ridge


Rintoul, SR and Sokolov, S and Williams, M and Pena-Molino, B and Rosenberg, MA and Bindoff, NL, Antarctic Circumpolar Current transport and barotropic transition at Macquarie Ridge, Geophysical Research Letters, 41, (20) pp. 7254-7261. ISSN 0094-8276 (2014) [Refereed Article]


Copyright Statement

Copyright 2014 American Geophysical Union

DOI: doi:10.1002/2014GL061880


©2014. American Geophysical Union. All Rights Reserved. Theory and numerical simulations suggest that topographic interactions are central to the dynamics of the Antarctic Circumpolar Current (ACC), but few observations are available to test these ideas. We use direct velocity measurements, satellite altimetry, and an ocean state estimate to investigate the interaction of the ACC with the Macquarie Ridge. Satellite altimeter data show that the Subantarctic Front crosses the ridge through a gap immediately north of Macquarie Island. Yearlong current meter records reveal strong deep mean flow (>-0.2-m-s-1 at 3000-m) and substantial transport (52 ± 8 × 106-m3-s-1) in the 50-km wide gap. The ACC becomes much more barotropic at the ridge. Acceleration of the deep jet is balanced by the ageostrophic along-gap pressure gradient, convergence of zonal momentum by the mean vertical velocity, and dissipation. The study helps explain how the ACC negotiates large topographic obstacles and highlights the role of local, nonlinear processes in the dynamical balance of the ACC. Key Points Antarctic Circumpolar Current velocity was measured at Macquarie RidgeThe current becomes more barotropic as it crosses the ridgeLocal nonlinear processes accelerate deep jet

Item Details

Item Type:Refereed Article
Keywords:Antarctic Circumpolar Current, barotropic, Macquarie Ridge, Southern Ocean, topographic interaction, transport
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical oceanography
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Oceanic processes (excl. in the Antarctic and Southern Ocean)
UTAS Author:Rintoul, SR (Dr Steve Rintoul)
UTAS Author:Sokolov, S (Dr Serguei Sokolov)
UTAS Author:Pena-Molino, B (Dr Beatriz Pena-Molino)
UTAS Author:Rosenberg, MA (Mr Mark Rosenberg)
UTAS Author:Bindoff, NL (Professor Nathan Bindoff)
ID Code:97455
Year Published:2014
Web of Science® Times Cited:20
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2014-12-17
Last Modified:2017-10-31
Downloads:376 View Download Statistics

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