Interannual variability in sea-ice thickness in the pack-ice zone off Lutzow-Holm Bay, East Antarctica

• Published in: Polar Science
• Main Authors: Sugimoto, F, Tamura, T, Shimoda, H, Uto, S, Simizu, D, Tateyama, K, Hoshino, S, Ozeki, T, Fukamachi, Y, Ushio, S, Ohshima, KI
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier Sci Ltd 2016
• Subjects: Earth Sciences; Oceanography; Physical Oceanography; Antarctic; East Antarctica; Antarc*; Antarctica; Polar Science; Sea ice
• Online Access: https://doi.org/10.1016/j.polar.2015.10.003; http://ecite.utas.edu.au/114489

Under the Japanese Antarctic Research Expedition (JARE) program, sea-ice thickness has been routinely monitored off LtzowHolm 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 ∼1.9m, mean thicknesses of observed sea-ice in 2010/11 and 2011/12 are exceptionally large, at ∼3.3 and ∼5.8m, 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 LtzowHolm Bay in summer are determined mainly by the large-scale pattern of atmospheric pressure in December.