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全文: "バフィン湾"
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  • 黒﨑 豊, 的場 澄人, 飯塚 芳徳, 庭野 匡思, 谷川 朋範, 安藤 卓人, 青木 輝夫
    雪氷研究大会講演要旨集
    2019年 2019 巻 B2-5
    発行日: 2019年
    公開日: 2019/11/10
    会議録・要旨集 フリー
  • 鈴木 勝彦, 賞雅 朝子, 深海 雄介, 飯塚 毅, 折橋 裕二, 新城 竜一
    日本地球化学会年会要旨集
    2019年 66 巻
    発行日: 2019年
    公開日: 2019/11/20
    会議録・要旨集 フリー

    182Hfは比較的短い半減期890万年で182Wにベータ壊変する。Hfは親石元素、Wは親鉄元素であるために、マントルとコアの間で分別が起き,マントルは高いHf/W比,コアは低いHf/W比を持つと考えられる。地球の初期,182Hfが消滅する前にコアが分離すれば,Hf/Wの高い始原マントルは高い182W/184W比を,Hf/W比の低いコアは低い182W/184W比を持っていることになる。本研究では,東アフリカAfarプルームに由来するエチオピアの玄武岩とアデン湾のMORBに適用した結果,いくつかの試料で,繰り返しの誤差の範囲を超えて負異常が得られた。コアの物質を含んでいる可能性が考えられるか,少なくとも地球ができて間もない頃の化学分別の痕跡を含んでいると考えられる。

  • 賞雅 朝子, 深海 雄介, 飯塚 毅, 鈴木 勝彦
    日本地球化学会年会要旨集
    2018年 65 巻
    発行日: 2018年
    公開日: 2018/11/21
    会議録・要旨集 フリー

    182Hfは、182Wに890万年という短い半減期でベータ壊変する。Hfは親石元素、Wは親鉄元素であるため、182W同位体は地球初期のコアの分離の際の分別過程を保存している可能性がある。本研究では超高精度のW同位体比分析手法を構築した。その過程で、183Wにおそらく原子核場シフトによる欠損が生じることを確認し、標準溶液も同様の分離をすることで信頼度の高いW同位体組成データを得ることに成功した。その方法を利用して、深部起源の玄武岩や中央海嶺玄武岩を分析したところ、現在のマントルの平均値が得られ、一方、ハワイ・ロイヒ島の3He/4Heの高い玄武岩ではマントル平均値より低い値が出ることが明らかになった。これは先行研究と調和的な結果であり、コア由来の182Wが欠乏したW同位体組成の影響を受けている可能性がある。

  • 星子 廉彰
    山階鳥類研究所研究報告
    1997年 29 巻 2 号 108-110
    発行日: 1997/10/30
    公開日: 2008/11/10
    ジャーナル フリー
    An individual of subspecies of Snow Goose, Anser caerulescens atlanticus, was first observed in March and April 1994, and continued to be observed in November 1995, March and November 1996, and March 1997 in central and eastern Hokkaido, Japan. This bird moved with flocks of Whitefronted Goose Anser albifrons or Middendorf's Bean Goose Anser fabalis middendorffii.
  • 藤井 理行
    地学雑誌
    1989年 98 巻 5 号 535-561
    発行日: 1989/10/25
    公開日: 2011/02/17
    ジャーナル フリー
    In recent years it has become obvious that two large ice sheets in Antarctica and Greenland are most ideal medium for past some 100k year record of global climate and environment. Compared with deep-sea sediment, polar ice core has some following advantages as record medium for palaeo-environment.
    1) High resolution because of high accumulation rale,
    2) High Accurcay because of inactive chemical at ice sheet surface, and
    3) Occulusion of air itself by the process of densification from firn to ice.
    Recent polar ice core studies have revealed 100 k-year cycle of climatic change and the synchronism between Northern and Southern Hemisphere. French and Soviet co-studies on Vostok ice core suggest that CO2 change have had an important climatic role during the late Pleistocene in amplifying the relatively weak orbital forcing. Thus ice core studies have provided fundamental information for the interpretation of glacial and interglacial climatic cycle. Furthermore, such studies on long term climatic changes basis on ice cores show the necessity of interdiciplinary interpretation on atmosphere-ocean-cryosphere climatic system and its relation to earth's orbital movement.
    Climatic cycle shorter than 100k-year shows regional characteristics. Hypsithermal, the warmest thousand years in Holocence appears in different ages; 8, 000-4, 100 years B. P. for Camp Century, Greenland core, 8, 000-4, 500 years B. P. for Byrd core, (9, 000)-5, 000 years B. P. for Mizuho core and 11, 000-8, 000 years B. P. for Dome-C core, Antarctica. So dose “little ice age”, the recent cold centuries. Polar ice cores reveal large volcanic eruption. Recent studies have suggested the climatic role of volcanic activities; The acidity of Byrd core indicates that a major volcanic event occurred for 150 years just when the transition period from the late glacial to the Holocence started.
    Thus polar ice core studies release valuable informations on palaeo-climate and environmont. However, further studies are requested for the detailed, quantitative and interdiciplinaly interpretation of 102-105 year climatic variation with high quality deep ice cores. Japanese Antarctic Dome Program at the top of Dronning Maud Land, Antarctica and European Greenland Ice Program (GRIP) are expepected to provide by-polar “standard” cores which will cover more than last climatic cycle.
  • 瀬川 高弘, 竹内 望
    日本微生物生態学会誌
    2016年 31 巻 2 号 57-64
    発行日: 2016/09/01
    公開日: 2017/04/07
    解説誌・一般情報誌 フリー
  • なぜ大気CO 2濃度が簿かったか?
    大場 忠道
    可視化情報学会誌
    1994年 14 巻 54 号 173-178
    発行日: 1994/07/15
    公開日: 2009/07/31
    ジャーナル フリー
  • 菊地 隆, 字野 弘勝, 細野 益男, 畠山 清
    海洋調査技術
    2004年 16 巻 1 号 1_19-1_27
    発行日: 2004年
    公開日: 2011/12/17
    ジャーナル フリー
    Accurate ocean current measurements near the magnetic dip pole have been carried out in the multi-year ice area of the central Arctic Ocean using ice-drifting buoy, J -CAD (JAMSTEC Compact Arctic Drifter). Because of weakness of the magnetic direction reference near the magnetic dip pole, we need to look more carefully into the compass malfunction in order to obtain accurate ocean current. Using the observational data from J-CAD 6 in 2003, we attempted heading data comparisons of attached compasses with azimuthal data calculated from GPS buoys. Results show that Watson Compass, which is 3-dimensional magneto-metric compass attached on the same cage of WorkHorse 300 kHz ADCP (WH-ADCP), can measure the correct heading with an accuracy of 4 degree over the entire J-CAD 6 trajectory. On the other hand, we found that WH-ADCP compass illustrated good results of heading measurements under the condition which the horizontal magnetic intensity is higher than 3000 nT. Also, we investigated a non-linear response of WH-ADCP compass from a comparison with Watson Compass, which are attached on J-CAD 4 in 2002. A non-linearity response of WH-ADCP compass was found with amplitude of ~20 degrees under the condition which the horizontal magnetic intensity is higher than 3000 nT. However, we can conclude that the heading data from WH-ADCP would be useful with an accuracy of 5 degrees after understanding the non-linear response of each compass.
  • 川合 美千代, 張 圓昕
    地球化学
    2019年 53 巻 4 号 173-182
    発行日: 2019/12/25
    公開日: 2019/12/25
    ジャーナル オープンアクセス

    Arctic Ocean is considered especially vulnerable to ocean acidification. Here we summarize current understandings of reasons of the vulnerability, state and future perspective of the ocean acidification in the Arctic Ocean, with an emphasis on regional variability. In general, Arctic Ocean has low calcium carbonate saturation state (Ω) and low pH buffer capacity to added carbon dioxide, because of its low temperature and dilution by various freshwater sources. In coastal shelf area, local physical and biogeochemical processes, such as river discharge and high biological activity, characterize Ω and pH in each region. Recent climate change is affecting each of these processes, to complicate ocean acidification in the Arctic Ocean. Despite the increasing attention, long-term observations are still insufficient for most part of the Arctic Ocean. Understanding and monitoring of Arctic Ocean would provide much knowledge about biogeochemical consequences of ocean acidification and concurrent climate change, in order to better predict future of our ocean.

  • 渡邉 英嗣, 田村 岳史
    日本リモートセンシング学会誌
    2015年 35 巻 1 号 2-9
    発行日: 2015/01/30
    公開日: 2015/07/30
    ジャーナル フリー
    Winter sea ice production in the Arctic coastal polynyas was compared between a satellite microwave-based estimate and a pan-Arctic sea ice-ocean model. The Alaskan coast, Novaya Zemlya, and North Water were chosen as target regions in this study. The interannual model experiment showed high correlation of sea ice production with the SSM/I-based variability from 1993 to 2013 in the Alaskan coast and Novaya Zemlya regions. On the other hand, the modeled production was frequently smaller than the satellite values. The modeling analyses suggested that offshore-ward sea ice transport and upward ocean heat transport were intensified in the same years, in the Alaskan coast and North Water regions. The wind stress with specific direction caused both the processes. Since the satellite algorithm used in this study did not include the ocean heat flux under sea ice, on which the wind-driven upwelling and turbulent mixing work, the improvement using open water mask was expected. For surface heat budget calculation, the model and satellite algorithm utilized different atmospheric datasets. Whereas the air temperature obtained from two major reanalysis data showed the close values in the Alaskan coast and Novaya Zemlya regions, the obvious temperature bias would be one of factors for an error in sea ice production in the North Water region. For further model improvements, the formulation of sea ice internal stress should be verified to more precisely represent polynya expanding processes. To update satellite algorithm, snow and fine-scale open lead would be key issues.
  • 布施 哲史, 金原 靖久, 佐藤 隆一
    石油技術協会誌
    2015年 80 巻 1 号 27-37
    発行日: 2015年
    公開日: 2017/05/10
    ジャーナル フリー

    Activities by man-kind are limited in the Arctic, high latitude place more than North 66°33′, because of its hostile environment. Only military base, scientific observation station, resources production sites and ethnic community exist. Oil and gas E&P activities have been made in limited area such as Timan-Pechora area and Yamal peninsula in Russia, Mackenzie delta in Canada, North-Lope in Alaska and Barents Sea. Especially for offshore exploration activities in Arctic, it is highly affected by sea ice. As observed by satellite image in Arctic, no or less ice affected areas are defined such as Barents Sea and Norwegian Sea. Ice covered area in the Arctic and near of the Arctic requires serious counter measures against sea ice for putting oil and gas exploration into execution. In this lecture, recent oil and gas exploration activities in the ice covered Arctic offshore area are reviewed. In addition, history and challenge for future on new exploration license area in northeast offshore Greenland, where Greenland Petroleum Development Ltd. (GPX), Japanese Joint Venture Company established by JOGMEC, INPEX, JX, JAPEX and MOECO, are discussed. Although increase of exploration activities in Arctic is expected in the days to come, there are several technical challenges and difficulties for matter of environmental protection. It is an important mission for E&P companies to overcome those challenges and difficulties and to promote frontier oil and gas exploration in the Arctic area.

  • 魚類学雑誌
    2001年 48 巻 1 号 68-74
    発行日: 2001/05/25
    公開日: 2010/06/28
    ジャーナル フリー
  • 藤井 清光, 乗本 治男, 浜野 英信, 石田 信一, 牧 康行, 佐々木 芳朗, 江川 堯, 鈴木 啓之, 吉田 圭二
    石油技術協会誌
    1975年 40 巻 6 号 343-351
    発行日: 1975年
    公開日: 2008/03/27
    ジャーナル フリー
    海洋石油開発の技術に関係した論文は,パネルディスカッションPD. 10の「深海底における掘さくの諸問題」における5論文,スペシャル•ペーパーSP. 3の「ダイポセミ」(Dyposemi),PD. 11の「深海における石油生産の諸問題」における5論文,PD. 15の「油田およびガス田の生産管理および制御の自動化」のうちの第3の論文「深海油田の遠隔操作」であり,合計12論文である。以下それらの論文の内容について紹介する。
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