Under the Japanese Antarctic Research Expedition (JARE) program, sea-ice thickness has been routinely monitored off Lützow–Holm Bay (East Antarctica) during the summer (mid-December to early January) since 2000/01, using an electromagnetic induction (EM) instrument onboard the icebreaker Shirase. Analysis of these data over a 10-year period, combined with visual observations using a simplified form of the ASPeCt (Antarctic Sea ice Processes and Climate) protocol, suggests a strong interannual variability in sea-ice thickness in this region. For the repeat pack-ice observation area, where the sea-ice thickness averaged over the nine seasons is ∼1.9 m, mean thicknesses of observed sea-ice in 2010/11 and 2011/12 are exceptionally large, at ∼3.3 and ∼5.8 m, respectively. This result is strongly related to regional patterns of sea ice dynamics. Ice convergence caused by anomalous northerly winds was particularly high in 2011/12, suggesting that the extremely thick ice observed in that season resulted largely from sea-ice deformation processes (including pressure ridging). Longer-term analysis of data from the past 34 years confirms that sea-ice conditions and thickness off Lützow–Holm Bay in summer are determined mainly by the large-scale pattern of atmospheric pressure in December.

Item Type:	Refereed Article
Keywords:	sea-ice thickness, electromagnetic-induction measurements, Antarctic Ocean, pack-ice zone, Lützow-Holm Bay
Research Division:	Earth Sciences
Research Group:	Oceanography
Research Field:	Physical Oceanography
Objective Division:	Environment
Objective Group:	Other Environment
Objective Field:	Antarctic and Sub-Antarctic Oceanography
Author:	Tamura, T (Dr Takeshi Tamura)
ID Code:	114489
Year Published:	2016
Web of Science® Times Cited:	1
Deposited By:	CRC-Antarctic Climate & Ecosystems
Deposited On:	2017-02-16
Last Modified:	2017-10-31
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