2017年01月, 北海道大学, 北海道大学平成28年度研究総長賞奨励賞　　　　　　　　　　　　　　　
宮本 淳

2016年02月, 北海道大学, 北海道大学平成27年度研究総長賞奨励賞　　　　　　　　　　　　　　　
宮本 淳

Development of deformational regimes and microstructures in the deep sections and overall layered structures of the Dome Fuji ice core, Antarctica
Tomotaka Saruya, Atsushi Miyamoto, Shuji Fujita, Kumiko Goto-Azuma, Motohiro Hirabayashi, Akira Hori, Makoto Igarashi, Yoshinori Iizuka, Takao Kameda, Hiroshi Ohno, Wataru Shigeyama, Shun Tsutaki
2024年01月05日

Development of crystal orientation fabric in the Dome Fuji ice core in East Antarctica: implications for the deformation regime in ice sheets
Tomotaka Saruya, Shuji Fujita, Yoshinori Iizuka, Atsushi Miyamoto, Hiroshi Ohno, Akira Hori, Wataru Shigeyama, Motohiro Hirabayashi, Kumiko Goto-Azuma
The Cryosphere, 16, 7, 2985, 3003, Copernicus GmbH, 2022年07月27日
研究論文（学術雑誌）, Abstract. The crystal orientation fabric (COF) of a polar ice sheethas a significant effect on the rheology of the ice sheet. With the aim ofbetter understanding the deformation regime of ice sheets, the workpresented here investigates the COF in the upper 80 % of the Dome FujiStation ice core in East Antarctica. Dielectric anisotropy (Δε) data were acquired as a novel indicator of the verticalclustering of COF resulting from vertical compressional strain within thedome. The Δε values were found to exhibit a generalincrease with depth, but with fluctuations over distances in the order of10–102 m. In addition, significant decreases in Δεwere found to be associated with depths corresponding to three major glacialto interglacial transitions. These changes in Δε areascribed to variations in the deformational history caused by dislocationmotion occurring from near-surface depths to deeper layers. Fluctuations inΔε over distances of less than 0.5 m exhibited a stronginverse correlation with Δε at depths greater thanapproximately 1200 m, indicating that they were enhanced during theglacial-interglacial transitions. The Δε data alsoexhibited a positive correlation with the concentration of chloride ions andan inverse correlation with the amount of dust particles in the ice core atgreater depths corresponding to decreases in the degree of c axis clustering.Finally, we found that fluctuations in Δε persisted toapproximately 80 % of the total depth of the ice sheet. These data suggestthat the factors determining the deformation of ice include theconcentration of chloride ions and the amount of dust particles, and thatthe layered contrast associated with the COF is preserved all the way fromthe near-surface to a depth corresponding to approximately 80 % of thethickness of the ice sheet. These findings provide important implicationsregarding further development of the COF under the various stress-strainconfigurations that the ice will experience in the deepest region,approximately 20 % of the total depth from the ice/bed interface.

Reconstruction of Sea Ice Concentration in Northern Baffin Bay Using Deuterium Excess in a Coastal Ice Core From the Northwestern Greenland Ice Sheet
Yutaka Kurosaki, Sumito Matoba, Yoshinori Iizuka, Masashi Niwano, Tomonori Tanikawa, Takuto Ando, Akira Hori, Atsushi Miyamoto, Shuji Fujita, Teruo Aoki
Journal of Geophysical Research: Atmospheres, 125, 16, American Geophysical Union (AGU), 2020年08月27日
研究論文（学術雑誌）

日本における《カレッジ・インパクト理論》の有効性の検証−日本の一大学のIRデータを使って−　　　　　　　　　　　　　　　
細川敏幸, 山田邦雅, 宮本淳
高等教育ジャーナル-高等教育と生涯学習-, 27, 45, 54, 2020年03月, ［査読有り］
日本語, 研究論文（学術雑誌）

IRデータによる学生層と大学層の形成と評価のシミュレーション　　　　　　　　　　　　　　　
山田邦雅, 宮本淳, 細川敏幸
高等教育ジャーナル－高等教育と生涯学習－, 26, 67, 76, 2019年03月

学習状況調査アンケートの動向ー米国と韓国の現在ー　　　　　　　　　　　　　　　
細川敏幸, 山田邦雅, 宮本淳
高等教育ジャーナル－高等教育と生涯学習－, 26, 59, 65, 2019年03月

米国高等教育機関における数学IRの訪問調査　　　　　　　　　　　　　　　
宮本淳, 山田邦雅, 細川敏幸
高等教育ジャーナル－高等教育と生涯学習－, 26, 77, 81, 2019年03月

教職員協働による教学に関するIR（Institutional Research）勉強会
宮本 淳, 出口寿久, 伊藤一馬, 川西奈津美, 河野未幸, 鈴木里奈, 高原めぐみ, 中川紗百合, 柳川仁美, 細川敏幸
高等教育ジャーナル－高等教育と生涯学習－, 25, 49, 54, 北海道大学高等教育推進機構, 2018年03月
日本語

グリーンランド南東ドームにおける 浅層アイスコア掘削と初期物理解析
飯塚芳徳, 的場澄人, 藤田秀二, 新堀邦夫, 山崎哲秀, 宮本淳, 堀彰,斉藤健, 古川崚仁, 杉山慎, 青木輝夫
低温科学, 75, 45, 52, 低温科学第75巻編集委員会, 2017年03月, ［査読有り］
日本語, グリーンランドにおける高涵養量域の圧密氷化過程の特徴の解明や近年の人為起源エアロゾルの変遷の解読を目的として，2015 年5 月にグリーンランド南東ドームにおいて，90.45 m の浅層コア掘削を実施した．掘削地点はタシーラク（アンマサリック）から185 km 北に位置している（SE-Dome；67.18°N，36.37°W，3170 m a.s.l.）．掘削孔の氷温は20 m 深において－20.9℃であった．2015 年8 月にコアが日本に輸送され，低温科学研究所の低温室において密度測定や電気伝導度測定などの初期コア解析が行われた．その結果，SE-Dome コアの氷化深度は83-86 m，涵養量は約1.0 m w.e. yr－1 であった．SE-Dome コアは氷床のドームとしては最も高涵養量の地域の一つである．圧密氷化過程を調べたところ，750 kg m－3 以上の密度域において，SE-Dome コアは通常の涵養量地域の浅層コアよりも変形しやすい特徴を持つことが分かった．In order to understand 1) temporal variations of anthropogenic aerosols from European regions under theIcelandic Low with high time resolution, and 2) the snow densification mechanism at a high accumulation dome inGreenland, we drilled a 90.45 m ice core in a high accumulation area of the southeastern Greenland Ice Sheet. Thedrilling site (SE-Dome; 67.18°N, 36.37°W, 3170 m a.s.l.) is located 185 km north of the town of Tasiilaq in southeasternGreenland. The ice temperature is -20.9℃ at 20 m depth, and the site has an average accumulation rate of 1.0 m w.e.yr-1 in water equivalent. The ice core exhibits distinct firn densification. The close-off density of 830 kg m-3 occursat 83.4-86.8 m depth, which is about 20 m shallower than predicted from an empirical model. In the region where thedensity ρ＞750 kg m-3, the densification appears faster than according to the empirical model.

A comparative analysis of the teaching and learning process of undergraduate students in Korea and Japan − Based on the cases of Seoul National University and Hokkaido University
Lee Heewon, Miyamoto Atsushi, Choi Jeung Yun
Journal of Higher Education and Lifelong Learning, 24, 24, 77, 95, 北海道大学高等教育推進機構, 2017年03月
英語, The purpose of this study was to investigate the teaching and learning processes experienced byuniversity students in Korea and Japan, and compare and analyze the higher education systems of the twocountries. For this purpose, surveys were conducted in Seoul National University (SNU) and HokkaidoUniversity (HU) based on questionnaires developed by the Korea Educational Development Institute and theInstitutional Research Consortium of the universities, respectively. Approximately 800 students from eachuniversity participated. Each of the surveys contained questions in six categories known to affect academicachievement: the level of class participation, extracurricular activities, active learning, cooperative learning,interaction with professors and academic competencies. After the surveys were concluded, the commonquestions in the two surveys were identified and the results of these questions were compared and analyzed.We found that students from HU had relatively higher levels of interaction with the faculty members,collaborative learning experiences and study hours, but students in SNU scored relatively higher with regardto their attitude in class, and satisfaction with university support, and also had an overall higher score in termsof the average of the learning outcomes. The results of this study will contribute to the analysis of the statusof studentsʼ learning processes in the universities in South Korea and Japan, and provide insights into areasthat require improvement. They will also help develop concrete measures to improve the quality of highereducation in both countries

State dependence of climatic instability over the past 720,000 years from Antarctic ice cores and climate modeling
Kenji Kawamura, Ayako Abe-Ouchi, Hideaki Motoyama, Yutaka Ageta, Shuji Aoki, Nobuhiko Azuma, Yoshiyuki Fujii, Koji Fujita, Shuji Fujita, Kotaro Fukui, Teruo Furukawa, Atsushi Furusaki, Kumiko Goto-Azuma, Ralf Greve, Motohiro Hirabayashi, Takeo Hondoh, Akira Hori, Shinichiro Horikawa, Kazuho Horiuchi, Makoto Igarashi, Yoshinori Iizuka, Takao Kameda, Hiroshi Kanda, Mika Kohno, Takayuki Kuramoto, Yuki Matsushi, Morihiro Miyahara, Takayuki Miyake, Atsushi Miyamoto, Yasuo Nagashima, Yoshiki Nakayama, Takakiyo Nakazawa, Fumio Nakazawa, Fumihiko Nishio, Ichio Obinata, Rumi Ohgaito, Akira Oka, Jun'ichi Okuno, Junichi Okuyama, Ikumi Oyabu, Frederic Parrenin, Frank Pattyn, Fuyuki Saito, Takashi Saito, Takeshi Saito, Toshimitsu Sakurai, Kimikazu Sasa, Hakime Seddik, Yasuyuki Shibata, Kunio Shinbori, Keisuke Suzuki, Toshitaka Suzuki, Akiyoshi Takahashi, Kunio Takahashi, Shuhei Takahashi, Morimasa Takata, Yoichi Tanaka, Ryu Uemura, Genta Watanabe, Okitsugu Watanabe, Tetsuhide Yamasaki, Kotaro Yokoyama, Masakazu Yoshimori, Takayasu Yoshimoto
SCIENCE ADVANCES, 3, 2, AMER ASSOC ADVANCEMENT SCIENCE, 2017年02月, ［査読有り］
英語, 研究論文（学術雑誌）, Climatic variabilities on millennial and longer time scales with a bipolar seesaw pattern have been documented in paleoclimatic records, but their frequencies, relationships with mean climatic state, and mechanisms remain unclear. Understanding the processes and sensitivities that underlie these changes will underpin better understanding of the climate system and projections of its future change. We investigate the long-term characteristics of climatic variability using a new ice-core record from Dome Fuji, East Antarctica, combined with an existing long record from the Dome C ice core. Antarctic warming events over the past 720,000 years are most frequent when the Antarctic temperature is slightly below average on orbital time scales, equivalent to an intermediate climate during glacial periods, whereas interglacial and fully glaciated climates are unfavourable for a millennial-scale bipolar seesaw. Numerical experiments using a fully coupled atmosphere-ocean general circulation model with freshwater hosing in the northern North Atlantic showed that climate becomes most unstable in intermediate glacial conditions associated with large changes in sea ice and the Atlantic Meridional Overturning Circulation. Model sensitivity experiments suggest that the prerequisite for the most frequent climate instabilitywith bipolar seesaw pattern during the late Pleistocene era is associated with reduced atmospheric CO2 concentration via global cooling and sea ice formation in the North Atlantic, in addition to extended Northern Hemisphere ice sheets.

A Firn Densification Process in the High Accumulation Dome of Southeastern Greenland　　　　　　　　　　　　　　　
Yoshinori Iizuka, Atsushi Miyamoto, Akira Hori, Sumito Matoba, Ryoto Furukawa, Takeshi Saito, Shuji Fujita, Motohiro Hirabayashi, Satoru Yamaguchi, Koji Fujita, Nozomu Takeuchi
Arctic, Antarctic, and Alpine Research, 49, 13, 27, 2017年01月, ［査読有り］

Physicochemical properties of bottom ice from Dome Fuji, inland East Antarctica
Hiroshi Ohno, Yoshinori Iizuka, Akira Hori, Atsushi Miyamoto, Motohiro Hirabayashi, Takayuki Miyake, Takayuki Kuramoto, Shuji Fujita, Takahiro Segawa, Ryu Uemura, Toshimitsu Sakurai, Toshitaka Suzuki, Hideaki Motoyama
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE, 121, 7, 1230, 1250, AMER GEOPHYSICAL UNION, 2016年07月, ［査読有り］
英語, 研究論文（学術雑誌）, The deepest ice in inland Antarctica is expected to preserve the oldest ice records and to potentially contain microorganisms. However, little is known about the physicochemical conditions in the deepest part of ice sheets. This study investigates the physicochemical properties of the bottom section (3000-3035m) of the Dome Fuji inland ice core, which is located immediately above unfrozen bedrock. The ubiquitous presence of air hydrates and the water isotope composition of ice comparable to the upper main ice core show that the bottom ice is meteoric. However, ion concentrations exhibit abnormal drops at the greatest depths (approximately below 3033m). In the same depth range, microscopic investigations reveal that considerable relocation of air hydrates and microinclusions (water-soluble impurities) occurs, suggesting that the observed reduction in ion concentration results from the segregation of inclusions to ice grain boundaries and the subsequent discharge of chemicals through liquid-water veins. Principal component analysis of ion data supports the meteoric-ice hypothesis, suggesting that the bottom ice had similar original chemistry through all depths. Statistical analyses of chemical data suggest that the water-soluble impurities attached to hydrates or dust (water-insoluble), the ice-soluble chemical species (such as chlorine), and solid particles are less affected by this chemical displacement phenomenon. It is also noteworthy that in the bottom ice, impurity chemicals, which are limiting nutrients for ice-dwelling microorganisms, are concentrated largely to ice-hydrate interfaces, where oxygen, another vital matter for aerobic microorganisms, is also enriched.

授業経験の質の差異が学生の学習態度・能力の自己評価に与える影響─2012～2014年学生調査の分析結果より─
宮本淳, 徳井美智代, 山田邦雅, 細川敏幸
高等教育ジャーナル─高等教育と生涯学習─, 23, 23, 79, 85, 北海道大学高等教育推進機構, 2016年03月
日本語

極ドームふじ近傍における次期深層氷床コア掘削
川村 賢二, 本山 秀明, 東 久美子, 藤田 秀二, 古川 晶雄, 中澤 文男, 青木 周司, 東 信彦, 阿部 彩子, 飯塚 芳徳, 植村 立, 内田 努, 大野 浩, 亀田 貴雄, 鈴木 利孝, 高田 守昌, 平林 幹啓, 藤田 耕史, 福井 幸太郎, 堀 彰, 堀内 一穂, 的場 澄人, 宮本 淳
雪氷研究大会講演要旨集, 2016, 194, 公益社団法人 日本雪氷学会／日本雪工学会, 2016年
日本語

過去3年の学習状況調査からみえる北大生の特徴―2014年IRプロジェクト活動報告―
徳井美智代, 宮本淳, 山田邦雅, 細川敏幸
高等教育ジャーナル─高等教育と生涯学習─, 22, 22, 67, 73, 北海道大学高等教育推進機構, 2015年03月
日本語

1-ブロモドデカン固定法による積雪のサンプリングおよび物理解析
大野 浩, 飯塚 芳徳, 宮本 淳, 川尻 竣三, 平松 雅宏, 八久保 晶弘
雪氷研究大会講演要旨集, 2015, 224, 224, 公益社団法人 日本雪氷学会／日本雪工学会, 2015年
日本語

永久凍土大規模地下氷の結晶性
大野 浩, 岩花 剛, 堀 彰, 宮本 淳, 飯塚 芳徳, 八久保 晶弘, 南 尚嗣, 内田 昌男, ラリー・ ヒンズマン, 曽根 敏雄
雪氷研究大会講演要旨集, 2015, 157, 157, 公益社団法人 日本雪氷学会／日本雪工学会, 2015年
日本語

連携5大学「一年生・上級生調査2011年」の北海道大学を中心とした比較分析（報告） : 教学評価IRネットワーク推進のために
安藤 厚, 細川 敏幸, 大沼 明, 山畑 倫志, 宮本 淳, 徳井 美智代, 山田 邦雅, 竹山 幸作
高等教育ジャーナル : 高等教育と生涯学習, 20, 1, 1, 102, 北海道大学高等教育推進機構 = Research Division for Higher Education, Institute for the Advancement of Higher Education, Hokkaido University, 2013年06月
日本語, Five Japanese universities (Doshisha University, Hokkaido University, Osaka Prefecture University, Konan University and Kwansei Gakuin University) worked together in the 2009- 2011 Freshman and Senior Survey for quality assurance and enhancement of college teaching and learning. This activity was supported by a Grant-in-Aid from the Ministry of Education, Culture, Sports, Science and Technology (MEXT). Comparative analysis of the 2011 Freshman and Senior Survey focusing on Hokkaido University showed: 1) that general education was good with rich first-year experiences, 2) the credit cap system and encouragement of self-study were working well, 3) the impact of the comprehensive admissions and new general education program, 4) the benefits of general education at a multidisciplinary university, and 5) that the satisfaction, sense of fulfillment and adaptation to university learning were higher among women. In addition, improvement of the career education program is necessary. The Freshman and Senior Survey will be continued for five more years by eight universities with the support of a new MEXT Grant-in-Aid. Through this activity plan advancement of the Institutional Assessment Network is expected.

連携5 大学「一年生・上級生調査2011 年」の北海道大学を中心とした比較分析（報告）─教学評価IR ネットワーク推進のために─　　　　　　　　　　　　　　　
安藤厚, 細川敏幸, 大沼明, 山畑倫志, 宮本淳, 徳井美智代, 山田邦雅, 竹山幸作
高等教育ジャーナル─高等教育と生涯学習─, 22, 67, 73, 2013年06月

Ｘ線ラウエ法による氷結晶の方位解析
宮本 淳
低温科学, 71, 59, 68, 北海道大学低温科学研究所 = Institute of Low Temperature Science, Hokkaido University, 2013年03月, ［査読有り］
日本語, 氷結晶の方位, 特に氷床コア試料の結晶ｃ軸方位は, 氷床の変形履歴を反映し, 氷床の力学的性質を決定する主要因子として詳細に調べられてきた. 測定装置は, 多くの時間と労力, 操作に熟練を要するユニバーサル・ステージから発展し, 近年は自動測定装置が用いられている. 2000m を超えるような深層コアの解析には自動化された測定装置が有効に用いられているが, 氷床深部に存在する非常に強い単極大型などの特殊な結晶方位分布の詳細を明らかにするには, 十分な測定精度を有していない. そこで, 筆者らはＸ線を用いた半自動化された結晶方位測定装置を開発し, 高精度測定を実現した. 本稿では, この装置の開発について述べ, 研究への適用例について紹介する.Ice crystal c-axis orientation of ice core samples have been investigated in detail as a major controlling factor of the mechanical properties of ice sheets. The universal stage was a common measurement device for c-axis orientation. The measurement procedure using this d...

Eemian interglacial reconstructed from a Greenland folded ice core
D. Dahl-Jensen, M. R. Albert, A. Aldahan, N. Azuma, D. Balslev-Clausen, M. Baumgartner, A. M. Berggren, M. Bigler, T. Binder, T. Blunier, J. C. Bourgeois, E. J. Brook, S. L. Buchardt, C. Buizert, E. Capron, J. Chappellaz, J. Chung, H. B. Clausen, I. Cvijanovic, S. M. Davies, P. Ditlevsen, O. Eicher, H. Fischer, D. A. Fisher, L. G. Fleet, G. Gfeller, V. Gkinis, S. Gogineni, K. Goto-Azuma, A. Grinsted, H. Gudlaugsdottir, M. Guillevic, S. B. Hansen, M. Hansson, M. Hirabayashi, S. Hong, S. D. Hur, P. Huybrechts, C. S. Hvidberg, Y. Iizuka, T. Jenk, S. J. Johnsen, T. R. Jones, J. Jouzel, N. B. Karlsson, K. Kawamura, K. Keegan, E. Kettner, S. Kipfstuhl, H. A. Kjær, M. Koutnik, T. Kuramoto, P. Köhler, T. Laepple, A. Landais, P. L. Langen, L. B. Larsen, D. Leuenberger, M. Leuenberger, C. Leuschen, J. Li, V. Lipenkov, P. Martinerie, O. J. Maselli, V. Masson-Delmotte, J. R. McConnell, H. Miller, O. Mini, A. Miyamoto, M. Montagnat-Rentier, R. Mulvaney, R. Muscheler, A. J. Orsi, J. Paden, C. Panton, F. Pattyn, J. R. Petit, K. Pol, T. Popp, G. Possnert, F. Prié, M. Prokopiou, A. Quiquet, S. O. Rasmussen, D. Raynaud, J. Ren, C. Reutenauer, C. Ritz, T. Röckmann, J. L. Rosen, M. Rubino, O. Rybak, D. Samyn, C. J. Sapart, A. Schilt, A. M.Z. Schmidt, J. Schwander, S. Schüpbach, I. Seierstad, J. P. Severinghaus, S. Sheldon, S. B. Simonsen, J. Sjolte, A. M. Solgaard, T. Sowers, P. Sperlich, H. C. Steen-Larsen, K. Steffen, J. P. Steffensen, D. Steinhage, T. F. Stocker, C. Stowasser, A. S. Sturevik, W. T. Sturges, A. Sveinbjörnsdottir, A. Svensson, J. L. Tison, J. Uetake, P. Vallelonga, R. S.W. Van De Wal, G. Van Der Wel, B. H. Vaughn, B. Vinther, E. Waddington, A. Wegner, I. Weikusat, J. W.C. White, F. Wilhelms, M. Winstrup, E. Witrant, E. W. Wolff, C. Xiao, J. Zheng
Nature, 493, 7433, 489, 494, 2013年01月24日, ［査読有り］
英語, 研究論文（学術雑誌）, Efforts to extract a Greenland ice core with a complete record of the Eemian interglacial (130,000 to 115,000 years ago) have until now been unsuccessful. The response of the Greenland ice sheet to the warmer-than-present climate of the Eemian has thus remained unclear. Here we present the new North Greenland Eemian Ice Drilling ('NEEM') ice core and show only a modest ice-sheet response to the strong warming in the early Eemian. We reconstructed the Eemian record from folded ice using globally homogeneous parameters known from dated Greenland and Antarctic ice-core records. On the basis of water stable isotopes, NEEM surface temperatures after the onset of the Eemian (126,000 years ago) peaked at 8 ± 4 degrees Celsius above the mean of the past millennium, followed by a gradual cooling that was probably driven by the decreasing summer insolation. Between 128,000 and 122,000 years ago, the thickness of the northwest Greenland ice sheet decreased by 400 ± 250 metres, reaching surface elevations 122,000 years ago of 130 ± 300 metres lower than the present. Extensive surface melt occurred at the NEEM site during the Eemian, a phenomenon witnessed when melt layers formed again at NEEM during the exceptional heat of July 2012. With additional warming, surface melt might become more common in the future. © 2013 Macmillan Publishers Limited. All rights reserved.

Diffraction-enhanced X-ray imaging under low-temperature conditions: non-destructive observations of clathrate gas hydrates.
Satoshi Takeya, Kazumasa Honda, Yoshito Gotoh, Akio Yoneyama, Kazuhiro Ueda, Atsushi Miyamoto, Takeo Hondoh, Akira Hori, Duo Sun, Ryo Ohmura, Kazuyuki Hyodo, Tohoru Takeda
Journal of synchrotron radiation, 19, Pt 6, 1038, 42, 2012年11月, ［査読有り］, ［国際誌］
英語, Diffraction-enhanced imaging (DEI) is a phase-contrast X-ray imaging technique suitable for visualizing light-element materials. The method also enables observations of sample-containing regions with large density gradients. In this study a cryogenic imaging technique was developed for DEI-enabled measurements at low temperature from 193 K up to room temperature with a deviation of 1 K. Structure-II air hydrate and structure-I carbon dioxide (CO(2)) hydrate were examined to assess the performance of this cryogenic DEI technique. It was shown that this DEI technique could image gas hydrate coexisting with ice and gas bubbles with a density resolution of about 0.01 g cm(-3) and a wide dynamic density range of about 1.60 g cm(-3). In addition, this method may be a way to make temperature-dependent measurements of physical properties such as density.

Diffraction-enhanced X-ray imaging under low-temperature conditions: non-destructive observations of clathrate gas hydrates
Satoshi Takeya, Kazumasa Honda, Yoshito Gotoh, Akio Yoneyama, Kazuhiro Ueda, Atsushi Miyamoto, Takeo Hondoh, Akira Hori, Duo Sun, Ryo Ohmura, Kazuyuki Hyodo, Tohoru Takeda
JOURNAL OF SYNCHROTRON RADIATION, 19, 1038, 1042, INT UNION CRYSTALLOGRAPHY, 2012年11月, ［査読有り］
英語, 研究論文（学術雑誌）, Diffraction-enhanced imaging (DEI) is a phase-contrast X-ray imaging technique suitable for visualizing light-element materials. The method also enables observations of sample-containing regions with large density gradients. In this study a cryogenic imaging technique was developed for DEI-enabled measurements at low temperature from 193 K up to room temperature with a deviation of 1 K. Structure-II air hydrate and structure-I carbon dioxide (CO2) hydrate were examined to assess the performance of this cryogenic DEI technique. It was shown that this DEI technique could image gas hydrate coexisting with ice and gas bubbles with a density resolution of about 0.01 g cm(-3) and a wide dynamic density range of about 1.60 g cm(-3). In addition, this method may be a way to make temperature-dependent measurements of physical properties such as density.

Crystal growth process of air-hydrate crystals in deep ice cores of Dome Fuji, Antarctica
Tsutomu Uchida, Atsushi Miyamoto, Takeo Hondoh
Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2011, 165, 2011年, ［査読有り］
英語, 研究論文（学術雑誌）

屈折コントラストＸ線イメージング法を用いた氷床コア中におけるエアハイドレートの三次元分布解析
竹谷 敏, 後藤 義人, 米山 明男, 上田 和浩, 宮本 淳, 本堂 武夫, 堀 彰, 兵藤 一行, 武田 徹
雪氷研究大会講演要旨集, 2011, 0, 28, 28, 公益社団法人 日本雪氷学会／日本雪工学会, 2011年, ［査読有り］
日本語

Subgrain boundaries in Antarctic ice quantified by X-ray Laue diffraction
Ilka Weikusat, Atsushi Miyamoto, Sergio H. Faria, Sepp Kipfstuhl, Nobuhiko Azuma, Takeo Hondoh
JOURNAL OF GLACIOLOGY, 57, 201, 111, 120, INT GLACIOL SOC, 2011年, ［査読有り］
英語, 研究論文（学術雑誌）, Ice in polar ice sheets undergoes deformation during its flow towards the coast. Deformation and recrystallization microstructures such as subgrain boundaries can be observed and recorded using high-resolution light microscopy of sublimation-edged sample surfaces (microstructure mapping). Subgrain boundaries observed by microstructure mapping reveal characteristic shapes and arrangements. As these arrangements are related to the basal plane orientation, full crystallographic orientation measurements are needed for further characterization and interpretation of the subgrain boundary types. X-ray Laue diffraction measurements validate the sensitivity of different boundary types with sublimation used by microstructure mapping for the classification. X-ray Laue diffraction provides misorientation values of all four crystal axes. Line scans across a subgrain boundary pre-located by microstructure mapping can determine the rotation axis and angle. Together with the orientation of the subgrain boundary this yields information on the dislocation types. Tilt and twist boundaries composed of dislocations lying in the basal plane, and tilt boundaries composed of nonbasal dislocations were found. A statistical analysis shows that nonbasal dislocations play a significant role in the formation of all subgrain boundaries.

Complete determination of ice crystal orientation using Laue X-ray diffraction method
Atsushi Miyamoto, Ilka Weikusat, Takeo Hondoh
JOURNAL OF GLACIOLOGY, 57, 201, 103, 110, INT GLACIOL SOC, 2011年, ［査読有り］
英語, 研究論文（学術雑誌）, Ice crystal orientation fabric data from ice cores contain important information concerning the internal structure and the flow behaviour of ice sheets. When ice cores are recovered from the Antarctic and Greenland ice sheets, crystal orientation measurements are performed immediately to obtain fundamental physical property information. In the past, we have measured the c-axis orientation of ice crystals by a manual optical method using a universal stage. This method is very time-consuming, involving tedious work in a cold laboratory. Recently, automated systems have been developed that enable measurement of c-axis orientation, grain size and other microstructures. However, in order to detect the full crystal orientation of an ice crystal, we also need information on its a-axis orientation. A variety of other crystal orientation measurement methods have previously been discussed, but some shortcomings for ice-core studies cannot be neglected. We have developed a crystal-orientation analysing device using the Laue X-ray diffraction method. As this device can measure the orientations of all crystal axes with high accuracy, it is possible to obtain new microstructure information on natural ice crystals. For the first time, we are able to quantify very low subgrain misorientation angles in polar icecore samples, allowing us to investigate micro-deformation features of individual crystals. Here we discuss the analysis process, which is customized to measure standard ice thin sections, and show preliminary results.

Crystal growth of air hydrates over 720 ka in Dome Fuji (Antarctica) ice cores: microscopic observations of morphological changes below 2000 m depth
Uchida Tsutomu, Miyamoto Atsushi, Shin'yama Atsushi, Hondoh Takeo
JOURNAL OF GLACIOLOGY, 57, 206, 1017, 1026, CAMBRIDGE UNIV PRESS, 2011年, ［査読有り］
英語, 研究論文（学術雑誌）, Air-hydrate crystals store most of the ancient air contained in deep ice sheets. We carried out microscopic observations of air-hydrate crystals below 2000 m depth within the ice core from Dome Fuji, Antarctica, to obtain their number and size distributions. We found that the number density continuously decreased with depth, whereas the average size increased, in contrast to findings from shallower depths. In addition, the characteristic perturbations in both number density and average size distribution with climatic changes almost disappeared, although they are clearly observed in shallow cores. These results indicate that the air-hydrate crystals grow considerably in deeper parts of the ice sheet, and this growth is accompanied by the diffusion of air molecules in the ice. The permeation coefficient of the air molecules in the ice sheet was estimated from the geometric parameters of the air-hydrate distributions. This is the first practical evidence comparable to the previous model estimations. It allows us to evaluate the impacts of the air-molecule migration in the ice sheet on the paleoclimatic information recorded in the deep ice cores.

Subgrain boundaries and related microstructural features in EDML (Antarctica) deep ice core
Weikusat Ilka, Kipfstuhl Sepp, Faria Sérgio H., Azuma Nobuhiko, Miyamoto Atsushi
Journal of Glaciology, 55, 191, 461, 472, International Glaciological Society, 2009年06月
英語, Subgrain boundaries revealed as shallow sublimation grooves on ice sample surfaces are a direct and easily observable feature of intracrystalline deformation and recrystallization. Statistical data obtained from the EPICA Dronning Maud Land (EDML) deep ice core drilled in East Antarctica cannot detect a depth region of increased subgrain-boundary formation. Grain-boundary morphologies show a strong influence of internal strain energy on the microstructure at all depths. The data do not support the classical view of a change of dominating recrystallization regimes with depth. Three major types of subgrain boundaries, reflecting high mechanical anisotropy, are specified in combination with crystal-orientation analysis.

南極氷床コアの結晶亜粒界間方位測定
宮本 淳, Weikusat Ilka, 本堂 武夫
雪氷研究大会講演要旨集, 2009, 22, 22, 公益社団法人 日本雪氷学会／日本雪工学会, 2009年
日本語

Physical layer structures of the deep part of the second Dome Fuji ice core
Atsushi Miyamoto, Takeo Hondoh
Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2008, 80, 2008年, ［査読有り］
英語, 研究論文（学術雑誌）

第２期ドームふじコア深層部の結晶組織解析
宮本 淳, 本堂 武夫
日本雪氷学会全国大会講演予稿集, 2007, 173, 173, 公益社団法人 日本雪氷学会, 2007年
日本語

A bipolar comparison of deep ice cores from Antarctica(Dome Fuji) and Greenland(GRIP).　　　　　　　　　　　　　　　
Shoji, H, Miyamoto, A, Shimohara, K, Watanabe O, Fujii, Y, Kamiyama, K, Motoyama, H, Azuma, K, Igarashi, M, Takata, M, Kohno, M, Nakazawa, T, Aoki, S, Kawamura, K, Narita, H, Kawada, K, Azuma, N, Fujita, S, Clausen, H.B, Johnson, S.J
Memoris of National Institute of Polar Research, S, 2007年, ［査読有り］

Ｘ線回折実験による結晶性の評価と氷床氷の力学的性質
宮本 淳, 本堂 武夫, 庄子 仁
日本雪氷学会全国大会講演予稿集, 2006, 107, 107, 公益社団法人 日本雪氷学会, 2006年
日本語

Ice fabric evolution process understood from anisotropic distribution of a-axis orientation on the GRIP (Greenland) ice core
Atsushi Miyamoto, Hitoshi Shoji, Akira Hori, Takeo Hondoh, Henrik B. Clausen, Okitsugu Watanabe
ANNALS OF GLACIOLOGY, VOL 42, 2005, 42, 47, 52, INT GLACIOLOGICAL SOC, 2005年, ［査読有り］
英語, 研究論文（学術雑誌）, To better understand how ice fabric evolves in polar ice sheets, we use X-ray diffraction to measure ice crystal orientations. X-ray measurement equipment which can measure the orientation of the c axis and a axis of each crystal in a thin section with high measurement accuracy was developed. In this study, we present a-axes orientation distribution of the deep part of the GRIP (Greenland summit) ice core. At some depths, we find an anisotropic distribution of a-axes orientation. Long-term uniaxial compression tests are also carried out on the GRIP ice core to investigate the ice fabric evolution process. The c-axis orientation distribution develops into a stronger single maximum as the strain increases up to about 20% strain. We find that the a axes of each grain also tend to cluster close to nearly a mutual direction. We discuss the development process of ice fabrics, taking into consideration the distribution of the a-axis orientations. It is suggested that these fabrics may be attributed to a local simple shear deformation in the deep part of an ice sheet.

Physical properties of the Dome Fuji deep ice core
Hondoh Takeo, Narita Hideki, Hori Akira, Ikeda-Fukazawa Tomoko, Fujii-Miyamoto Michiko, Ohno Hiroshi, Shiraiwa Takayuki, Mae Shinji, Fujita Shuji, Fukazawa Hiroshi, Fukumura Taku, Shoji Hitoshi, Kameda Takao, Miyamoto Atsushi, Azuma Nobuhiko, Wang Yun, Kawada Kunio, Nishio Fumihiko, Motoyama Hideaki, Watanabe Okitsugu
Memoirs of National Institute of Polar Research, Special Issue, 57, 63, 71, 2003年03月, ［査読有り］
英語, Recent results of physical analyses of the Dome Fuji ice core are summarized with special attention to new methods introduced in the present studies．Microphysical processes which affect the ice core records are reviewed to better understand the paIeoclimatic and paleoenvironmental signals stored.

A bipolar comparison of deep ice cores from Antarctica（Dome Fuji）and Greenland（GRIP） (scientific paper)
Shoji Hitoshi, Miyamoto Atsushi, Shimohara Kimiko, Watanabe Okitsugu, Fujii Yoshiyuki, Kamiyama Kokichi, Motoyama Hideaki, Goto-Azuma Kumiko, Igarashi Makoto, Takata Morimasa, Kohno Mika, Fujita Shuji, Nakazawa Takakiyo, Aoki Shuji, Kawamura Kenji, Narita Hideki, Kawada Kunio, Azuma Nobuhiko, Saito Takashi, Clausen Henrik B, Johnsen Sigfus J
Memoirs of National Institute of Polar Research, Special Issue, 57, 86, 93, 2003年03月, ［査読有り］
英語, Oxgen isotope ratio and chemistry profiles were compared to find the corresponding interstadials during the Wisconsin Ice Age between the GRIP (Greenland) and Dome Fuji (Antarctica) deep ice core data for the past one hundred and sixty thousand years. Eight interstadials in GRIPδ^<18>O profile were found to correspond to those in Dome Fuji δ^<18>O profile. Eleven interstadials in GRIPδ^<18>O profile were found to correspond to those in Dome Fuji chemistry (calcium, nitrate and sulfate) profile, which is better suited for the purpose of interstadial search than the δ^<18>O profile at Dome Fu...

Cloudy band observations for annual layer counting on the GRIP and NGRIP, Greenland, deep ice core samples (scientific note)
Shimohara Kimiko, Miyamoto Atsushi, Hyakutake Kinji, Shoji Hitoshi, Takata Morimasa, Kipfstuhl Sepp
Memoirs of National Institute of Polar Research, Special Issue, 57, 161, 167, 2003年03月, ［査読有り］
英語, Cloudy band stratigraphy was observed in the GRIP and NGRIP, Greenland ice cores. Gray value profiles obtained from the photographic recording were analyzed to extract annual layer signals. Simple counting of gray value peaks is effective enough when annual layer thickness is relatively small (smaller than approximately 20 mm), but smoothing of the gray value profile is needed when annual layer thickness is larger. Smoothing can be done by adopting a running mean over a range of half of annual layer thickness estimated from ice flow modeling. A comparison of the DEP profile with the gray va...

Mechanical anisotropy of deep ice core samples by uniaxial compression tests (scientific paper)
Miyamoto Atsushi, Shimohara Kimiko, Hyakutake Kinji, Shoji Hitoshi, Narita Hideki, Hondoh Takeo
Memoirs of National Institute of Polar Research, Special Issue, 57, 168, 177, 2003年03月, ［査読有り］
英語, Mechanical anisotropy of ice core samples has been observed in various uniaxial compression tests. The c-axis orientation distribution is the primary influence on the mechanical behavior of ice cores. A strong single-maximum fabric pattern is observed in the deep parts of the ice sheet. In this region, polycrystalline ice is very hard along the vertical axis; however, it easily shears along the horizontal plane. Thus, by acquiring the distribution of c-axis orientations throughout the ice sheet, the mechanical anisotropy of ice sheet flow behavior can be understood. Analysis of fabric measu...

The effect of hydrostatic pressure on crack formation in ice single crystals
Miyamoto Atsushi, Shoji Hitoshi, Hyakutake Kinji
Memoirs of National Institute of Polar Research, Special Issue, 56, 287, 294, 2002年03月, ［査読有り］
英語, Many tiny cracks are observed near the surface of deep ice cores drilled from polar ice sheets. These cracks probably form during the ice core drilling process at hydrostatic pressure, which increases linearly with depth. We studied crack formation in ice experimentally by deforming ice single crystals using a uniaxial compression apparatus with controlled hydrostatic pressure. The uniaxial compressive stress was applied to ice samples under a hydrostatic pressure of 20 Mpa at -18℃. A constant strain rate was set at 〜10^<-7>s^<-1>. The c-axis orientations of the ice single crystals were par...

Microscopic observations on microtomed surface of ice
Hyakutake Kinji, Moribe Atsushi, Miyamoto Atsushi, Shimohara Kimiko, Shoji Hitoshi
Memoirs of National Institute of Polar Research, Special Issue, 56, 295, 301, 国立極地研究所, 2002年03月, ［査読有り］
英語, Surface hollows appearing after microtome shaving were observed on poly-and single crystal specimens under an optical microscope in a cold room laboratory. Characteristic shell-shaped hollows appeared with their major axis perpendicular to the shaving direction. Fewer hollows appeared at specimen surfaces when the basal plane of the ice crystal was parallel or perpendicular to the specimen surface. The results observed could be easily interpreted if cleavage cracks form parallel or perpendicular to the basal plane near the blade edge during the microtome shaving process.

アセスメント・ポリシーの考え方—アセスメント・ポリシー研究会報告—　　　　　　　　　　　　　　　
細川敏幸, 山田邦雅, 宮本淳, 高等教育ジャーナル-高等教育と生涯学習-, 25, 69, 73, 2018年03月
日本語, 記事・総説・解説・論説等（大学・研究所紀要）

南極ドームふじ近傍における次期深層氷床コア掘削
川村賢二, 川村賢二, 川村賢二, 本山秀明, 本山秀明, 東久美子, 東久美子, 藤田秀二, 藤田秀二, 古川晶雄, 古川晶雄, 中澤文男, 中澤文男, 青木周司, 東信彦, 阿部彩子, 阿部彩子, 飯塚芳徳, 植村立, 内田努, 大野浩, 亀田貴雄, 鈴木利孝, 高田守昌, 平林幹啓, 藤田耕史, 福井幸太郎, 堀彰, 堀内一穂, 的場澄人, 宮本淳, 雪氷研究大会講演要旨集(Web), 2016, 2016年

グリーンランド南東ドームにおける浅層掘削計画-掘削報告と初期コア解析-
飯塚 芳徳, 的場 澄人, 大藪 幾美, 山崎 哲秀, 門田 萌, 新堀 邦夫, 青木 輝夫, 斉藤 健, 宮本 淳, 古川 崚仁, 藤田 秀二, 堀 彰, 山口 悟, 大野 浩, 鈴木 利孝, 植村 立, 関 宰, 本山 秀明, 雪氷研究大会講演要旨集, 2015, 190, 2015年
公益社団法人 日本雪氷学会／日本雪工学会, 日本語

グリーンランド南東ドームにおける浅層掘削計画 -掘削報告と初期コア解析-
飯塚芳徳, 的場澄人, 大藪幾美, 山崎哲秀, 門田萌, 新堀邦夫, 青木輝夫, 斉藤健, 宮本淳, 古川崚仁, 藤田秀二, 堀彰, 山口悟, 大野浩, 鈴木利孝, 植村立, 関宰, 本山秀明, 雪氷研究大会講演要旨集(Web), 2015, 190(J‐STAGE), 2015年
日本語

グリーンランド深層氷床コア掘削計画(NEEM計画)
東久美子, 青木周司, 東信彦, 飯塚芳徳, 植竹淳, 川村賢二, 神田啓史, 倉元隆之, 小端拓郎, 笹公和, 佐藤基之, 瀬川高弘, 高村近子, 中澤高清, 平林幹啓, 藤井理行, 藤田秀二, 堀彰, 堀内一穂, 三宅隆之, 宮本淳, 本山秀明, 雪氷研究大会講演要旨集, 2010, 2010年

North Greenland Eemian Ice Driling
Kumiko Goto-Azuma, Jun Uetake, Kenji Kawamura, Hiroshi Kanda, Takayuki Kuramoto, Takuro Kobashi, Takahiro Segawa, Chiikako Takamura, Motohiro Hirabayashi, Yoshiyuki Fujii, Shuji Fujita, Takayuki Miyake, Hideaki Motoyama, Shuji Aoki, Takakiyo Nakazawa, Nobuhiko Azuma, Motoyuki Sato, Yoshinori Iizuka, Atsushi Miyamoto, Kimikazu Sasa, Akira Hori, Kazuho Horiuchi, Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2010, 4, 2010年01月01日

Study on spatial distributions of water-soluble microparticles preserved in polar ice sheet
T. Sakurai, A. Miyamoto, Y. Iizuka, T. Hondoh, T. Uchida, S. Fujita, Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research, 2010, 109, 109, 2010年01月01日
公益社団法人 日本雪氷学会／日本雪工学会, 日本語

European Geosciences Union General Assembly 参加報告
東 久美子, 東 信彦, 大野 浩, 香内 晃, 河野 美香, 藤田 秀二, 堀川 信一郎, 本堂 武夫, 宮本 淳, 雪氷 : 日本雪氷協會雜誌, 67, 4, 366, 371, 2005年07月15日
日本雪氷学会, 日本語

第7回国際南極雪氷シンポジウム報告　　　　　　　　　　　　　　　
堀彰, 藤井理行, 河村俊行, 前野英生, 宮本淳, 飯塚芳徳, 雪氷, 66巻1号、69-72, 2004年

First InterICE Workshop 参加報告
宮本 淳, 雪氷 : 日本雪氷協會雜誌, 65, 6, 551, 552, 2003年11月15日
日本語

第二期Dome Fuji氷床コアプロジェクトに用いる光学層位記録装置の開発
高田 守昌, 飯塚 芳徳, 庄子 仁, 宮本 淳, Kipfstuhl Sepp, 本堂 武夫, 藤田 秀二, 藤井 理行, 南極資料, 47, 3, 328, 337, 2003年11月
第二期ドームふじ氷床コアプロジェクトの現場解析において,簡便に光学層位を記録するため,専用装置を開発した.この装置は,二次元的な光の散乱強度を氷床コアサンプルの深さ方向に沿って連続的に測定する.我々は,この装置のハードウェアおよび制御ソフトウェアを開発した.この結果,経験のないオペレーターでも容易に測定可能な,自動測定装置が完成した.測定速度は5mm/sを想定しており,この場合,現場処理解析の基本長である1.5mのサンプルを約6分間で測定可能である.この装置は第44次越冬隊が南極ドームふじ観測拠点に搬入し,第45次夏隊から始まる深層コア掘削の現場解析処理に使用される予定である., 国立極地研究所, 日本語

第6回国際南極雪氷シンポジウム報告
藤田 秀二, 東 久美子, 飯塚 芳徳, 堀 彰, 宮本 淳, 雪氷, 61, 1, 51, 54, 1999年01月15日
日本雪氷学会, 日本語

Antarctica and Global Change : Interactions and Impacts国際シンポジウム報告
白井 孝行, 宮本 淳, 本井 達夫, 牛尾 収輝, 藤井 理行, 小西 啓之, 雪氷, 60, 1, 59, 63, 1998年01月15日
日本雪氷学会, 日本語

PLASTIC DEFORMATION PROPERTIES OF GREENLAND ICE CORE SAMPLES
SHOJI Hitoshi, NARITA Hideki, MIYAMOTO Atsushi, WATANABE Okitsugu, CLAUSEN Henrik B., KIPFSTUHL Josef, Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology, 11, 249, 249, 1997年11月
Mechanical property studies have been conducted on deep ice core samples to understand the flow dynamics of large polar ice sheets. Uniaxial compression tests were done both on the Dye 3 and GRIP ice core samples from Greenland. The stress axis is inclined 45 degree from core axis in order to have information on horizontal shear deformation behavior of an ice sheet. The results were analyzed by using an enhancement factor, E. C-axis orientation fabric is a dominant factor for E values and can be estimated from vertical compression strain (N. AZUMA and A. HIGASHI, 1985) if preferred orientation is developed by crystal rotation process without recrystalization. E values from Dye 3 and GRIP samples were plotted with normalized depth (=depth/ice thickness), which is a measure of vertical compression strain. Down to a depth around 60% of ice thickness, the E value stays constant around l, and increases below that depth as expected from the single maximum fabric in deeper places. Below a depth around 70% of ice thickness, E exceeds about 10 and E of GRIP ice samples is higher than that of Dye 3 samples in general. This difference could be attributed to chemical impurity contents and/or ice stratigraphic features such as cloudy bands., 国立極地研究所, 英語

ICE CRYSTAL ORIENTATION DISTRIBUTIONS IN LARGE ICE MASSES
SHOJI Hitoshi, MIYAMOTO Atsushi, NARITA Hideki, Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology, 11, 246, 246, 1997年11月
Flow behavior of large ice sheets is affected mainly by c-axis orientation fabric, and the fabric formation is caused by the anisotropic characteristics in the plastic deformation property of ice crystal. There are three processes involved in fabric formation; i.e. crystal rotation (AZUMA and HIGASHI, 1985), recrystalization and polygonization. Two types of crystal fabric development with depth have been observed in deep polar ice cores. Type A shows crystal fabric changes from a random distribution near the surface to vertical cluster development with depth under vertical compression and to a strong single maximum pattern near the bottom under simple shear deformation (Camp Century, Dye 3,GRIP and Byrd ice cores). Type B shows fabric changes from a random distribution near the surface to a large girdle development with depth, where the c-axis direction is almost perpendicular to the uniaxial tensile strain axis along the ice flow direction (Mizuho and Vostok ice cores). To estimate vertical compressive strain, ε and uniaxial tensile strain, γ, the following equations were assumed : ε=-ln(y/H), γ=-2ln(y/H), where y is height from the bottom and H is ice thickness. For Type A cores, the c-axis lies mainly along the vertical core direction with depth and a single maximum fabric appears at depth for about ε=150%, except for Byrd core samples which shows single maximum fabric appearance for about ε=80%. For Type B cores, crystal fabrics developments with an increase in γ are quite similar to each other., 国立極地研究所, 英語

Preliminary discussion of physical properties of the Dome Fuji shallow ice core in 1993, Antarctica
Watanabe Okitsugu, Shimada Wataru, Narita Hideki, Miyamoto Atsushi, Tayuki Kazushige, Hondoh Takeo, Kawamura Toshiyuki, Fujita Shuji, Shoji Hitoshi, Enomoto Hiroyuki, Kameda Takao, Kawada Kunio, Yokoyama Kotaro, 庄子 仁, 榎本 浩之, 亀田 貴雄, Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology, 11, 1, 8, 1997年11月
To make a pilot-hole for deep core drilling at Dome Fuji Station, East Queen Maud Land, Antarctica, shallow ice core drilling was conducted to a depth of 112.59 m by electro-mechanical drill. Core logging, measurements of impermeability and bulk density were conducted in situ and most of another analysis was done in Japan．Much depth hoar developed at Dome Fuji Station. However, it did not influence the densification rate, which mainly depends on temperature. Air bubble close-off starts from about 90 m depth. Much accumulation at one time occurs during marine cyclones at Dome Fuji Station., 国立極地研究所, 英語

AN ATTEMPT AT DEFORMATION TESTS OF DEEP ICE CORE SAMPLES CONTAINING CLOUDY BANDS
MIYAMOTO Atsushi, SHOJI Hitoshi, NARITA Hideki, WATANABE Okitsugu, CLAUSEN Henrik B, HONDOH Takeo, Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology, 11, 87, 93, 1997年11月
We conducted detailed mechanical property investigations of deep polar ice core samples. In order to understand the effect of cloudy band structure on deformation of ice core samples, uniaxial compression tests were carried out by using the GRIP ice core containing cloudy bands. The uniaxial compression tests were performed under the conditions of constant strain rate (Type A) and constant load (Type B) at -15℃. The enhancement factor (Es) correlates with the schmid factor (F) that indicates c-axis orientation development with F less than 0.46. The Es of ice specimens with F larger than 0.4..., 国立極地研究所, 英語

DEPTH-AGE CALCULATIONS FOR LARGE POLAR ICE SHEETS
MIYAMOTO Atsushi, HONDOH Takeo, SHOJI Hitoshi, Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology, 10, 152, 152, 1996年09月
Ice cores contain important information on climatic conditions in the past. All data sets should be interpreted and discussed on the basis of a reliable core chronology. The uncertainly of ice core dating by a flow model increases for deeper parts of ice sheets. Nevertheless, in this pilot study we estimated a relation between depth and age at Dome Fuji Station, Antarctica, using the Dansgaard-Johnsen model (W. DANSGAARD and S. J. JOHNSEN : J. Glaciol., 8,215,1969) with past accumulation rate changes taken into consideration. The ice flow velocity profiles can be approximated and characterized with one parameter, h, the distance from the bedrock. The vertical strain rate is assumed to be constant from the surface down to the level h=h^* and, further, decreasing linearly to zero at the bedrock. A value of 1200m was adopted for h^* at Dome Fuji Station, which is the value used for the GRIP ice core analysis. Dome Fuji Station, Antarctica, and GRIP site, Greenland, are both located at the summit positions of the ice sheets and the ice thickness values are nearly equal to each other (about 3000m). Depth-age calculations were also performed for h^*=0 to study the influence of parameter h^*. Depths for the Holocene/Wisconsin boundary were obtained as 376 and 370m, respectively. This suggests that the Holocene/Wisconsin boundary is not so sensitive to the ice flow pattern at Dome Fuji Station. Depths for the Wisconsin/Sangamon boundary were also calculated at the assumption that the accumulation rates during the Wisconsin age period was 1/2 (case 1) and 2/3 (case 2) of its presentday values. The resultant estimates were about 1450m (case 1) and 1670m (case 2), respectively. This confirms that the accumulation rate during a glacial period is a major factor which determines a depth-age relation at deeper levels in large ice sheets in ice flow modeling., 国立極地研究所, 英語