Editorial Type:
Article
Article Type:
Research Article

Improving Estimates of the Antarctic Circumpolar Current Streamlines in Drake Passage

Yueng-Djern Lenn Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California

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Teresa K. Chereskin Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California

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Janet Sprintall Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California

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Print Publication:
01 May 2008
DOI:
https://doi.org/10.1175/2007JPO3834.1
Page(s):
1000–1010
Restricted access

Abstract

Accurately resolving the mean Antarctic Circumpolar Current (ACC) is essential for determining Southern Ocean eddy fluxes that are important to the global meridional overturning circulation. Previous estimates of the mean ACC have been limited by the paucity of Southern Ocean observations. A new estimate of the mean surface ACC in Drake Passage is presented that combines sea surface height anomalies measured by satellite altimetry with a recent dataset of repeat high-resolution acoustic Doppler current profiler observations. A mean streamfunction (surface height field), objectively mapped from the mean currents, is used to validate two recent dynamic height climatologies. The new streamfunction has narrower and stronger ACC fronts separated by quiescent zones of much weaker flow, thereby improving on the resolution of ACC fronts observed in the other climatologies. Distinct streamlines can be associated with particular ACC fronts and tracked in time-dependent maps of dynamic height. This analysis shows that varying degrees of topographic control are evident in the preferred paths of the ACC fronts through Drake Passage.

* Current affiliation: School of Ocean Sciences, Bangor University, Anglesey, Wales, United Kingdom

Corresponding author address: Yueng-Djern Lenn, School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey, LL59 5AB Wales, United Kingdom. Email: yueng@coast.ucsd.edu

Abstract

Accurately resolving the mean Antarctic Circumpolar Current (ACC) is essential for determining Southern Ocean eddy fluxes that are important to the global meridional overturning circulation. Previous estimates of the mean ACC have been limited by the paucity of Southern Ocean observations. A new estimate of the mean surface ACC in Drake Passage is presented that combines sea surface height anomalies measured by satellite altimetry with a recent dataset of repeat high-resolution acoustic Doppler current profiler observations. A mean streamfunction (surface height field), objectively mapped from the mean currents, is used to validate two recent dynamic height climatologies. The new streamfunction has narrower and stronger ACC fronts separated by quiescent zones of much weaker flow, thereby improving on the resolution of ACC fronts observed in the other climatologies. Distinct streamlines can be associated with particular ACC fronts and tracked in time-dependent maps of dynamic height. This analysis shows that varying degrees of topographic control are evident in the preferred paths of the ACC fronts through Drake Passage.

* Current affiliation: School of Ocean Sciences, Bangor University, Anglesey, Wales, United Kingdom

Corresponding author address: Yueng-Djern Lenn, School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey, LL59 5AB Wales, United Kingdom. Email: yueng@coast.ucsd.edu

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