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Seasonality of warm water intrusions onto the continental shelf near the Totten Glacier

Citation

Silvano, A and Rintoul, SR and Kusahara, K and Pena-Molino, B and van Wijk, E and Gwyther, DE and Williams, GD, Seasonality of warm water intrusions onto the continental shelf near the Totten Glacier, Journal of Geophysical Research: Oceans pp. 1-18. ISSN 2169-9275 (2019) [Refereed Article]


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DOI: doi:10.1029/2018JC014634

Abstract

Warm Modified Circumpolar Deep Water (MCDW) from the Southern Ocean drives rapid basal melt of the Totten Ice Shelf on the Sabrina Coast (East Antarctica), affecting the mass balance of the grounded Totten Glacier. Recent observations show that MCDW intrudes onto the continental shelf through a depression at the shelf break. Here we investigate such intrusions by combining (1) new oceanographic and bathymetric observations collected for two consecutive years by profiling floats in the depression south of the shelf break, (2) oceanographic measurements collected by conductivity‐temperature‐depth‐instrumented seals on continental slope, and (3) an ocean model. The depression provides a pathway for persistent inflow of warm (0‐1C) MCDW to the inner shelf. In austral autumn and early winter MCDW intrusions were up to 0.5C warmer and were are ~75 m thicker than in spring and summer. The seasonality of the flow on the continental slope explains the seasonality of the intrusions. The MCDW layer on the continental slope is warmer and thicker to the east of the depression than to the west. In autumn and early winter a strong, top‐to‐bottom westward current (Antarctic Slope Current) transports the warmer and thicker MCDW layer along the slope and is diverted poleward at the eastern entrance of the depression. A bottom‐intensified eastward current (Antarctic Slope Undercurrent) develops in other months, allowing cooler and thinner intrusions to enter the depression from the west. Our study illustrates how circulation on the Antarctic slope regulates the ocean heat delivery to the continental shelf and ultimately to the ice shelves.

Item Details

Item Type:Refereed Article
Keywords:Antarctica, oceanography
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical Oceanography
Objective Division:Environment
Objective Group:Climate and Climate Change
Objective Field:Climate Variability (excl. Social Impacts)
UTAS Author:Silvano, A (Mr Alessandro Silvano)
UTAS Author:Rintoul, SR (Dr Steve Rintoul)
UTAS Author:Kusahara, K (Dr Kazuya Kusahara)
UTAS Author:Pena-Molino, B (Dr Beatriz Pena-Molino)
UTAS Author:van Wijk, E (Ms Esmee van Wijk)
UTAS Author:Gwyther, DE (Dr David Gwyther)
UTAS Author:Williams, GD (Associate Professor Guy Williams)
ID Code:133777
Year Published:2019
Deposited By:Oceans and Cryosphere
Deposited On:2019-07-10
Last Modified:2019-07-10
Downloads:0

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