Physical processes of formation of climate signals in deposited snow in inland plateau of the Antarctic Ice Sheet

2014 Fiscal Year Final Research Report

• Project/Area Number: 24241007
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Environmental dynamic analysis
• Research Institution: National Institute of Polar Research
• Principal Investigator: FUJITA Shuji 国立極地研究所, 研究教育系, 准教授 (30250476)
• Co-Investigator(Renkei-kenkyūsha): HACHIKUBO Akihiro 北見工業大学, 工学部, 准教授 (50312450) ; IIZUKA Yoshinori 北海道大学, 低温科学研究所, 助教 (40370043) ; HORI Akira 北見工業大学, 工学部, 准教授 (60280856) ; KAWAMURA Kenji 国立極地研究所, 研究教育系, 准教授 (90431478) ; KOBASHI Takuro 国立極地研究所, 研究教育系, 外来研究員 (00527129) ; KIM Koui 国立極地研究所, 研究教育系, 助教 (10609796)
• Research Collaborator: KIPFSTUHL Josef アルフレッドウェゲナー極地海洋研究所, シニア研究員
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 南極 / アイスコア / フィルン / 雪 / 変形 / 変態 / 気候変動 / 氷

Outline of Final Research Achievements

In order to better understand the physical processes of formation of climate signals in deposited snow in inland plateau of the Antarctic Ice Sheet of polar firn, firn cores from Dome Fuji, Antarctica and NEEM Camp, Greenland, were investigated. Layers with initially smaller density and smaller geometrical anisotropy deform preferentially throughout the densification process due to textural effects. Second, layers having a higher concentration of chloride and/or fluoride ions deform preferentially during a limited period from the ice sheet surface until smoothing out of layered ions by diffusion. We hypothesize that these ions softened firn due to modulation of dislocation movement. Moreover, firn differs markedly between the sites in terms of strength of geometrical anisotropy, mean rate of densification, and density fluctuation. We hypothesize that these differences are caused by textural effects resulting from differences in depositional conditions within various spatial scales.

Free Research Field

雪氷学、極域科学、アイスコア研究