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Seasonal evolution of an ice-shelf influenced fast-ice regime, derived from an autonomous thermistor chain

Citation

Hoppmann, M and Nicolaus, M and Hunkeler, PA and Heil, P and Behrens, L-K and Konig-Langlo, G and Gerdes, R, Seasonal evolution of an ice-shelf influenced fast-ice regime, derived from an autonomous thermistor chain, Journal of Geophysical Research: Oceans, 120, (3) pp. 1703-1724. ISSN 2169-9275 (2015) [Refereed Article]


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Copyright 2015 The Authors

DOI: doi:10.1002/2014JC010327

Abstract

Ice shelves strongly interact with coastal Antarctic sea ice and the associated ecosystem by creating conditions favorable to the formation of a sub-ice platelet layer. The close investigation of this phenomenon and its seasonal evolution remains a challenge due to logistical constraints and a lack of suitable methodology. In this study, we characterize the seasonal cycle of Antarctic fast ice adjacent to the Ekström Ice Shelf in the eastern Weddell Sea. We used a thermistor chain with the additional ability to record the temperature response induced by cyclic heating of resistors embedded in the chain. Vertical sea-ice temperature and heating profiles obtained daily between November 2012 and February 2014 were analyzed to determine sea-ice and snow evolution, and to calculate the basal energy budget. The residual heat flux translated into an ice-volume fraction in the platelet layer of 0.18 ± 0.09, which we reproduced by a independent model simulation and agrees with earlier results. Manual drillings revealed an average annual platelet-layer thickness increase of at least 4 m, and an annual maximum thickness of 10 m beneath second-year sea ice. The oceanic contribution dominated the total sea-ice production during the study, effectively accounting for up to 70% of second-year sea-ice growth. In summer, an oceanic heat flux of 21 W m−2 led to a partial thinning of the platelet layer. Our results further show that the active heating method, in contrast to the acoustic sounding approach, is well suited to derive the fast-ice mass balance in regions influenced by ocean/ice-shelf interaction, as it allows subdiurnal monitoring of the platelet-layer thickness.

Item Details

Item Type:Refereed Article
Keywords:Antarctic sea ice, ice shelves, sub-ice platelet layer, Antarctic fast ice
Research Division:Earth Sciences
Research Group:Physical Geography and Environmental Geoscience
Research Field:Glaciology
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
UTAS Author:Heil, P (Dr Petra Heil)
ID Code:100206
Year Published:2015
Web of Science® Times Cited:10
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2015-05-07
Last Modified:2017-10-30
Downloads:246 View Download Statistics

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