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Deep bottom mixed layer drives intrinsic variability of the Antarctic Slope Front

Citation

Huneke, WGC and Klocker, A and Galton-Fenzi, BK, Deep bottom mixed layer drives intrinsic variability of the Antarctic Slope Front, Journal of Physical Oceanography, 49 pp. 3163-3177. ISSN 0022-3670 (2019) [Refereed Article]


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DOI: doi:10.1175/JPO-D-19-0044.1

Abstract

The Antarctic Slope Front (ASF) is located along much of the Antarctic continental shelf break and helps to maintain a barrier to the movement of Circumpolar Deep Water (CDW) onto the continental shelf. The stability of the ASF has a major control on cross-shelf heat transport and ocean-driven basal melting of Antarctic ice shelves. Here, the ASF dynamics are investigated for continental shelves with weak dense shelf water (DSW) formation, which are thought to have a stable ASF, common for regions in East Antarctica. Using an ocean process model, this study demonstrates how offshore bottom Ekman transport of shelf waters leads to the development of a deep bottom mixed layer at the lower continental slope, and subsequently determines an intrinsic variability of the ASF. The ASF variability is characterized by instability events that affect the entire water column and occur every 5–10 years and last for approximately half a year. During these instability events, the cross-shelf density gradient weakens and CDW moves closer to the continent. Stronger winds increase the formation rate of the bottom mixed layer, which causes a subsequent increase of instability events. If the observed freshening trend of continental shelf waters leads to weaker DSW formation, more regions might be vulnerable for the ASF variability to develop in the future.

Item Details

Item Type:Refereed Article
Keywords:Antarctic Slope Front, ocean model, coastal flows, currents, fronts, ocean dynamics
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical oceanography
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Understanding climate change
Objective Field:Effects of climate change on Antarctic and sub-Antarctic environments (excl. social impacts)
UTAS Author:Huneke, WGC (Ms Wilma Huneke)
UTAS Author:Klocker, A (Dr Andreas Klocker)
UTAS Author:Galton-Fenzi, BK (Dr Ben Galton-Fenzi)
ID Code:137058
Year Published:2019
Web of Science® Times Cited:1
Deposited By:Oceans and Cryosphere
Deposited On:2020-01-30
Last Modified:2020-03-20
Downloads:3 View Download Statistics

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