Some Implications of Ekman Layer Dynamics for Cross-Shelf Exchange in the Amundsen SeaShow others and affiliations
Responsible organisation
2012 (English)In: Journal of Physical Oceanography, ISSN 0022-3670, E-ISSN 1520-0485, Vol. 42Article in journal (Refereed) Published
Abstract [en]
The exchange of warm, salty seawater across the continental shelves off West Antarctica leads to subsurface glacial melting at the interface between the ocean and the West Antarctic Ice Sheet. One mechanism that contributes to the cross-shelf transport is Ekman transport induced by along-slope currents over the slope and shelf break. An investigation of this process is applied to the Amundsen Sea shelfbreak region, using recently acquired and historical field data to guide the analyses. Along-slope currents were observed at transects across the eastern and western reaches of the Amundsen slope. Currents in the east flowed eastward, and currents farther west flowed westward. Under the eastward-flowing currents, hydrographic isolines sloped upward paralleling the seabed. In this layer, declining buoyancy forces rather than friction were bringing the velocity to zero at the seabed. The basin water in the eastern part of the shelf was dominated by water originating from 800-1000-m depth off shelf, suggesting that transport of such water across the shelf frequently occurs. The authors show that arrested Ekman layers mechanism can supply deep water to the shelf break in the eastern section, where it has access to the shelf. Because no unmodified off-shelf water was found on the shelf in the western part, bottom layer Ekman transport does not appear a likely mechanism for delivery of warm deep water to the western shelf area. Warming of the warm bottom water was most pronounced on the western shelf, where the deep-water temperature increased by 0.6 degrees C during the past decade.
Place, publisher, year, edition, pages
2012. Vol. 42
Keywords [en]
peninsula continental-shelf pine island glacier ice shelf water masses bottom slope circulation boundary model currents Oceanography
National Category
Natural Sciences
Research subject
SWEDARP 2008/09, Oden Southern Ocean 2008/09
Identifiers
URN: urn:nbn:se:polar:diva-1941DOI: 10.1175/jpo-d-11-041.1OAI: oai:DiVA.org:polar-1941DiVA, id: diva2:810209
Note
ISI Document Delivery No.: 009IC Times Cited: 8 Cited Reference Count: 32 Wahlin, A. K. Muench, R. D. Arneborg, L. Bjork, G. Ha, H. K. Lee, S. H. Alsen, H. National Science Foundation (NSF); Swedish Polar Research Secretariat; Swedish Research Council (SRC); SRC [824-2008-6439, 2010-19172-73868-33, 621-2008-2689]; NSF through NSF [OPP-0125602, ANT-0440656]; ONR [N00014-03-1-0067]; KOPRI [PE11040]; Vinnova The cruise Oden Southern Ocean 2008/09 was carried out on IB Oden, and we are grateful for help and logistic support from the captain and crew. Bengt Liljebladh, Kevin Pedigo, and Jeremy Lucke provided expert technical assistance with preparations as well as during the cruise. The cruise was supported by National Science Foundation (NSF), Swedish Polar Research Secretariat, and the Swedish Research Council (SRC). We are grateful to Sharon Stammerjohn and Xiaoyun Yuan for providing comments on the manuscript and data from the Oden 2007 cruise. The data from the World Ocean Database were compiled by the National Oceanographic Data Center of NOAA. Wahlin was funded by SRC (Grants 824-2008-6439 and 2010-19172-73868-33) and Vinnova, Bjork was funded by SRC (Grant 824-2008-6439), Arneborg was funded by SRC (Grant 621-2008-2689), and Muench was funded by NSF through NSF Grants OPP-0125602 and ANT-0440656 and ONR Grant N00014-03-1-0067 to Earth & Space Research. Ha and Lee were supported by KOPRI Grant PE11040. 8 Amer meteorological soc Boston Oceanography
2015-05-062015-05-062017-12-04