著者
MATOBA Sumito(的場澄人) MOTOYAMA Hideaki(本山秀明) FUJITA Koji(藤田耕史) YAMASAKI Tetsuhide(山崎哲秀) MINOWA Masahiro(箕輪昌紘) ONUMA Yukihiko(大沼友貴彦) KOMURO Yuki(小室悠紀) AOKI Teruo(青木輝夫) YAMAGUCHI Satoru(山口悟) SUGIYAMA Shin(杉山慎) ENOMOTO Hiroyuki(榎本浩之)
出版者
公益社団法人 日本雪氷学会
雑誌
Bulletin of Glaciological Research (ISSN:13453807)
巻号頁・発行日
vol.33, pp.7-14, 2015 (Released:2015-12-08)
参考文献数
20
被引用文献数
10

During spring 2014, we drilled an ice core on the northwestern Greenland Ice Sheet, recovering a core of total length 225m. We also conducted stratigraphic observations, measurements of the density of the ice core, near-infrared photography of the ice core, preparation of liquid samples for chemical analysis, and measurements of borehole temperature. The pore close-off depth was 60m, and the temperature in the borehole was −25.6°C at a depth of 10m. In addition, we conducted snow-pit observations, ice-velocity and surface-elevation measurements using the global positioning system (GPS), meteorological observations, and installation of an automated weather station (AWS).
著者
波多 俊太郎 杉山 慎
雑誌
JpGU-AGU Joint Meeting 2020
巻号頁・発行日
2020-03-13

Glaciar Pío XI, the largest glacier in the Southern Patagonia Icefield (SPI), has advanced over the last several decades in contrast to a shrinking trend of other glaciers in the SPI. The mechanism of the unique behavior is unclear due to lack of detailed observations. To investigate the mechanism of the recent advance of Glaciar Pío XI, we measured ice-front position and glacier surface elevation by using satellite data from 2000 to 2018. Ice-fronts of all separated termini showed advancing trend. The largest advance of 1400 m was observed at the southern main front. Glacier surface elevation increased by 35 m as a mean over the ablation area during the study period, and the rate of elevation change increased by 240% from Period 1 (2000–2007) to Period 2 (2007–2017/18). The rate of elevation change was non-uniformly distributed over time and space; i.e. rapid thickening (~20 m a−1) was observed in a limited area during Period 1, whereas only slightly positive rate (~2.4 m a−1) was observed over the entire region during Period 2. Previous studies reported ice speed deceleration near the southern main front, suggesting decrease in frontal ablation over the study period. Based on satellite image observations from 2000 to 2018, we attribute the deceleration to deposition of sediment and formation of shoal in front of the glacier. In the accumulation area, increase in snow accumulation is reported for a period from 1980 to 2015. Therefore, we propose the reduction in frontal ablation and increase in accumulation as possible mechanisms of the recent advancing and thickening trend of Glaciar Pío XI. Our data illustrate details of advancing despite a retreating trend in adjacent glaciers in Patagonia.
著者
杉山 慎
出版者
低温科学第76巻編集委員会
雑誌
低温科学 (ISSN:18807593)
巻号頁・発行日
vol.76, pp.169-177, 2018-03-31

南極氷床は地球に存在する淡水の60%以上を蓄積し,巨大な淡水リザーバとしての役割を担っている.その変動は海水準,海洋循環,アルベド,地殻隆起など,地球の気候システムに大きな影響を与える.近年の観測技術の向上によって,この氷床が氷を失いつつあることが明らかになってきた.南極沿岸部において顕著な質量損失が報告されており,海洋の変化に影響を受けた棚氷と溢流氷河の縮退がその原因と考えられている.本稿では,南極氷床の特徴と地球環境に果たす役割,氷床変動のメカニズムについて概説した後,近年の氷床変動とそれを駆動する氷床・海洋相互作用について最近の知見を紹介する.
著者
青木 輝夫 本山 秀明 竹内 望 的場 澄人 堀 雅裕 八久保 晶弘 山口 悟 田中 泰宙 岩田 幸良 杉浦 幸之助 兒玉 裕二 藤田 耕史 朽木 勝幸 庭野 匡思 保坂 征宏 橋本 明弘 谷川 朋範 田中 泰宙 植竹 淳 永塚 尚子 杉山 慎 本吉 弘岐 下田 星児 本谷 研
出版者
気象庁気象研究所
雑誌
基盤研究(S)
巻号頁・発行日
2011-04-01

グリーンランド氷床上での現地観測から、涵養域ではアルベド低下に対するブラックカーボン(BC)等積雪不純物の寄与は小さく、積雪粒径増加効果の方が大きいことが分かった。また2012年7月の顕著な表面融解には下層雲からの長波放射が効いていた。消耗域では表面の不純物中に微生物が大量に含まれ、アルベド低下へ大きく寄与していた。衛星観測から2000年以降の氷床表面アルベドの低下原因を解析した結果、涵養域では積雪粒径の経年増加が主要因で、消耗域では裸氷域と微生物を含む暗色域の拡大が原因であった。内陸域で深さ223mの氷床コアを掘削し、その解析からBC濃度は1920-30年に現在の数倍程度高いことが分かった。
著者
杉山 慎 近藤 研
出版者
公益社団法人 日本雪氷学会
雑誌
雪氷 (ISSN:03731006)
巻号頁・発行日
vol.83, no.2, pp.193-204, 2021 (Released:2021-09-29)
参考文献数
48

北極域では,温暖化に伴う環境変化が人間社会に影響を与えつつある.本稿ではその事例として,グリーンランドで発生した氷河流出河川の洪水災害を紹介し,数値モデルを用いた氷河融解と流出量解析について解説する.2015 年7 月21 日と2016 年8 月2 日に,グリーンランド北西部カナック氷河の流出河川が増水し,村と空港を結ぶ道路が破壊された.これらの事象を詳しく解析するために,2017-2019 年に氷河と河川で実施した観測に基づいて,氷河融解・流出モデルを構築した.この数値モデルによって2015年と2016年の流出量を再現したところ,両年の洪水時における流出量は,一時間値で9.1 および19.9m3 s−1 と示された.2015 年の洪水は,氷河全域平均で51mm w.e. d−1に及ぶ雪氷融解によるもので,2015-2019年では2 番目に顕著な融解イベントであった.一方で2016年の洪水は,2015-2019 年で2 番目の規模を持つ豪雨(90mm d−1)によるものであった.数値実験の結果は,気温上昇,強風・降雨の頻度増加,裸氷域の拡大などの環境変化が,氷河流出量の増加傾向をもたらすことを示している.
著者
安仁屋 政武 MARINSEK Sebastián 紺屋 恵子 縫村 隆行 津滝 俊 刀根 健太 BARCAZA Gonzalo SKVARCA Pedro 杉山 慎 青木 賢人 松元 高峰 安間 了 内藤 望 榎本 浩之 堀 和明
出版者
公益社団法人 日本雪氷学会
雑誌
氷河情報センター (ISSN:13453807)
巻号頁・発行日
no.29, pp.1-17, 2011
被引用文献数
2 9

The Glaciological Research Project in Patagonia (GRPP) 2006-2009 was carried out with several objectives at Glaciar Perito Moreno of the Hielo Patag&oacute;nico Sur (HPS), in the area of the Hielo Patag&oacute;nico Norte (HPN) and along the Pacific coast. At Glaciar Perito Moreno, hot water drilling was carried out at about 5km upstream from the terminus, reaching the glacier bottom at ca. 515m, in order to monitor subglacial water pressure. Good positive correlations among air temperature, subglacial water pressure and glacier flow speed were found. Based on <sup>14</sup>C dating of tree and organic samples, it is proposed that Glaciar Perito Moreno made two Little Ice Age (LIA) advances at AD1600-1700 and ca. 130-100y BP (AD1820-50). Fan deltas located at the mouth of big rivers around Lago General Carrera (Buenos Aires) and Lago Cochrane (Pueyrredon), in the area east of the HPN, were investigated to elucidate their development. The variations of 21 outlet glaciers of the HPN elucidated from aerial surveys for 2004/05-2008/09 revealed an areal loss of 8.67km<sup>2</sup> in four years. A general slowing down of retreats was observed with a few exceptions. Meteorological measurements at Glaciar Exploradores of the HPN from 2005 to 2009 indicate that air temperature ranged from 17.4&deg;C to -10.5&deg;C. The total annual precipitation was about 3000mm. Glacier surface melt was observed at two spots. Sediment and water discharges from the glacier showed that while water discharge fluctuated a lot, suspended sediment concentration was rather stable in summer. A single channel seismic profiling during the JAMSTEC MR08-06 cruise identified a probable submerged moraine formed before the last glacial maximum (LGM) in the Golfo de Penas, south of Taitao Peninsula. Piston coring along the Chilean coast further indicates that ice-rafted debris recorded the LGM and earlier Late Pleistocene events of the glacial advance.
著者
近藤 研 杉山 慎
雑誌
JpGU-AGU Joint Meeting 2020
巻号頁・発行日
2020-03-13

The Antarctic ice sheet drains ice into the ocean through floating ice shelves and outlet glaciers, which play key roles in the mass balance of the Antarctic ice sheet. Since iceberg calving and ice shelf basal melting are major ablation processes of the ice sheet, understanging the dynamics of floating ice is important. Land-fast sea ice affects the stability of ice shelves by exerting battressing force on the ice front. For example, previous studies reported glacier front retreat, disintegration of ice shelves and ice flow acceleration after breakup of sea ice in front of glaciers (e.g. Miles et al., 2017). Lützow-Holm Bay located in East Antarctica is usually covered with land-fast sea ice all year round, but a large portion of sea ice broke up in April 2016 (Aoki et al., 2017). In order to investigate the impact of the sea ice break up on outlet glaciers in the region, we carried out satellite observations on Langhovde Glacier, one of the outlet glaciers terminating in Lützow-Holm Bay. Glacier terminus position was deliniated from 2000 to 2020, using Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and Landsat 8 Operational Land Imager (OLI) imagery. Changes in glacier surface area near the calving front were devided by the width of the calving front to obtain mean retreat/advance distance. Ice flow velocity field from 2014 to 2020 was measured, by applying a feature tracking method (Sakakibara and Sugiyama, 2014) to Landsat 8 OLI image pairs.Terminus position has been relatively stable from 2000 to 2012, with only small fluctuations within a range of 200 m. The glacier then advanced by 400 m from 2012 to 2016. After 2016, the year of the land-fast sea ice break up, the terminus retreated rapidly by 720 m by 2020 as a result of large calving events in 2016 and 2019. The glacier front reached the most retreated position since 2000. After the sea ice breakup, ice speed increased from 110 m a−1 in 2017 to 135 m a−1 in 2019. The results of this study suggest the glacier had been stabilized by the land-fast sea ice by 2016. Rapid retreat and acceleration after the breakeup indicate significant influence of sea ice on the dynamics of outlet glaciers in Antarctica.ReferencesMiles, B.W.J. and Stokes, C.R. and Jamieson, S.S.R (2017), Simultaneous disintegration of outlet glaciers in Porpoise Bay (Wilkes Land), East Antarctica, driven by sea ice break-up, The Cryosphere, 11, 427-442.Aoki, S. (2017), Breakup of land-fast sea ice in Lützow-Holm Bay, East Antarctica, and its teleconnection to tropical Pacific sea surface temperatures, Geophys. Res. Lett., 44, 3219–3227.Sakakibara, D., and S. Sugiyama (2014), Ice-front variations and speed changes of calving glaciers in the Southern Patagonia Icefield from 1984 to 2011, J. Geophys. Res. Earth Surf., 119, 2541–2554.
著者
白岩 孝行 的場 澄人 山縣 耕太郎 杉山 慎 飯塚 芳徳 YOSHIKAWA Kenji 佐々木 央岳 福田 武博 對馬 あかね
出版者
総合地球環境学研究所
雑誌
基盤研究(B)
巻号頁・発行日
2007

北部北太平で知られている気候レジームシフトと生物基礎生産量変動との関係について調べるために、アラスカ山脈オーロラピーク近傍に発達する氷河において氷コアを採取し、鉄濃度の分析を行った。その結果、10年間の平均鉄沈着量は8.8mg m^<-2>・yr^<-1>で、2001年2002年は、それぞれ、29、19mg m^<-2>・yr^<-1>だった。30m深の海洋表面混合層への鉄の供給は、10年間の平均値では、植物プランクトンを増殖させるほどの影響がないが、2001年、2002年の大規模黄砂時には影響を与えうることが推測された。