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Frontal structure and transport in the northwestern Weddell Sea

Thompson, Andrew F. and Heywood, Karen J. (2008) Frontal structure and transport in the northwestern Weddell Sea. Deep Sea Research Part 1, 55 (10). pp. 1229-1251. ISSN 0967-0637. doi:10.1016/j.dsr.2008.06.001. https://resolver.caltech.edu/CaltechAUTHORS:20130124-111441058

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Abstract

Hydrographic data from the Antarctic Drifter Experiment: Links to Isobaths and Ecosystems (ADELIE) project are analyzed to determine the frontal structure and transport along a section across the continental shelf and slope in the northwestern Weddell Sea. The flow is dominated by three barotropic northward flowing currents: the Antarctic Coastal Current, the Antarctic Slope Front and the Weddell Front. The strongest baroclinic flows are confined to the region between the Slope Front and the Weddell Front over the steepest part of the continental slope. The Antarctic Coastal Current flows over the continental shelf near a local steepening in the bathymetry and has a transport of ~1.3 Sv. The Antarctic Slope Front is found approximately 25 km offshore of the shelf break in 800 m of water. The Slope Front, which is associated with a transport of ~4 Sv, exhibits peak velocities above the bottom that reach 35cm s^(-1)as detected by lowered acoustic Doppler profiler (LADCP) measurements. A third northward current is found between the 2500 and 3000 m isobaths, corresponding to a local break in the topography. Potential temperature–salinity diagrams show that the change in water mass properties across the deep front is similar to the change found across the Weddell Front in the northern Weddell Sea. This suggests that the deep front is a crossing of the Weddell Front further upstream in the Weddell Gyre. The Weddell Front accounts for ~17 Sv of northward transport across the section. A deep outflow is observed all along the continental slope between the Slope Front and the Weddell Front. Transport within the deep outflow is localized in two to three distinct cores that are tied to topographical features. The total transport across the ADELIE section is 46 ± 8 Sv. This value exceeds previous estimates because the full-depth and de-tided LADCP measurements allowed the narrow (~20 km) frontal currents to be resolved, leading to more accurate estimates of the barotropic component of the flow. We discuss the physical processes that may lead to the formation and maintenance of these fronts.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1016/j.dsr.2008.06.001DOIArticle
http://www.sciencedirect.com/science/article/pii/S0967063708001222PublisherArticle
ORCID:
AuthorORCID
Thompson, Andrew F.0000-0003-0322-4811
Heywood, Karen J.0000-0001-9859-0026
Additional Information:© 2008 Elsevier Ltd. Received 24 September 2007. Received in revised form 6 June 2008. Accepted 12 June 2008. Available online 19 June 2008. We would like to thank all who contributed to the success of the ADELIE research cruise, especially the officers and crew of the RRS James Clark Ross. In particular, Nuno Nunes and Angelika Renner were invaluable in collecting the LADCP and ADCP data during the cruise. We would also like to thank Deb Shoosmith for her assistance in processing the shipboard ADCP data. We acknowledge the comments from the anonymous reviewers, which led to significant improvements of the manuscript. The cruise was supported by the UK Natural Environment Research Council (NERC) through the Antarctic Funding Initiative, AFI6/25.
Funders:
Funding AgencyGrant Number
Environment Research Council (NERC)AFI6/25
Subject Keywords:Antartic Slope Front; Weddell Sea; Topography; Hydrography; LADCP
Issue or Number:10
DOI:10.1016/j.dsr.2008.06.001
Record Number:CaltechAUTHORS:20130124-111441058
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20130124-111441058
Official Citation:Andrew F. Thompson, Karen J. Heywood, Frontal structure and transport in the northwestern Weddell Sea, Deep Sea Research Part I: Oceanographic Research Papers, Volume 55, Issue 10, October 2008, Pages 1229-1251, ISSN 0967-0637, 10.1016/j.dsr.2008.06.001. (http://www.sciencedirect.com/science/article/pii/S0967063708001222
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:36569
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:24 Jan 2013 21:17
Last Modified:09 Nov 2021 23:23

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