チャクチ・ベーリング海における乱流混合の観測研究：生物生産・気候変動への影響評価

• Project Area: Ocean Mixing Processes: Impact on Biogeochemistry, Climate and Ecosystem
• Project/Area Number: 16H01596
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Complex systems
• Research Institution: The University of Tokyo (2017); Japan Agency for Marine-Earth Science and Technology (2016)
• Principal Investigator: 川口 悠介 東京大学, 大気海洋研究所, 助教 (00554114)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Project Status: Completed (Fiscal Year 2017)
• Budget Amount: ¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000); Fiscal Year 2017: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000); Fiscal Year 2016: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
• Keywords: 北極海 / 気象擾乱 / 内部重力波 / 生物生産 / ベーリング海峡 / 乱流混合 / 地球温暖化 / 海洋物理 / 気候変動 / 北極海・チャクチ海 / ベーリング海 / 海洋乱流 / 海洋微生物群集 / 植物プランクトン / 多重貫入構造 / 海洋物理・陸水学

Outline of Annual Research Achievements

本申請課題では、北極海南西部・季節海氷域における海洋混合過程を明らかにすべく、船舶による現地調査を行い、そのデータ解析を行う。本年度は、「みらい」北極航海「MR17-05C」に参加し、ベーリング海峡周辺の海洋混合について観測を実施した。特に、ベーリング海峡の南部に位置するアナディル海峡を通過する流れの不安定性に注目し、乱流観測や流れの直接観測を実施した。調査の結果、秋に特徴的な海面水温フロント（冷水パッチ構造）について、キーとなる物理過程の観測に成功した。要点を端的に述べると、当海峡の上流に位置するアナディル湾系の水が海峡を通過し、チコリフ湾に貫入する。この時、鉛直下部の低温水が、周囲の水と激しく混合しながら表層付近にまで湧昇し、相対的に低温な領域を海面に作り出す様子が観測された。これは、カナダ海盆など、北極海内部の広い範囲において現場の熱収支や水温分布に影響を与え、結果的に海氷の多寡にまで影響する可能性がある。今後はこの混合プロセスの発生機構や条件の解明に向けてさらなる現場調査・解析を進める予定である。
北極海の生物生産への影響に関しては、チャクチ陸棚域において2013年に実施した観測（MR13-06）から重要な共著論文が発表された（Fujiwara et al. 2018）。この研究は、当該海域に暴風による流れが発生した際、海底のセジメント物質が巻き上がり、植物プランクトンや海洋微生物の繁殖につながる様子を実施のデータから示した。また、その際、優占的に卓越するプランクトンの種類や規模に関して、蛍光高度計を用いて統計学手法から定量化に成功した点は評価に値する。ここで得られた成果は、秋の北極海で頻発する気象擾乱に対する海洋の応答について、他分野（物・生・化）が相互連携し、体系的な成果をあげた研究として重要な位置付けにある。

Research Progress Status

29年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

29年度が最終年度であるため、記入しない。

Research Products

• [Int'l Joint Research] インハ大学/韓国極地研究所（KOPRI）(韓国)
• [Journal Article] Changes in phytoplankton community structure during wind-induced fall bloom on the central Chukchi shelf (2018)
  • Author(s): Fujiwara Amane, Shigeto Nishino, Kohei Matsuno, Jonaotaro Onodera, Yusuke Kawaguchi
  • Journal Title: Polar Biology Volume: - Issue: 6 Pages: 1279-1295
  • DOI: 10.1007/s00300-018-2284-7
  • Peer Reviewed / Open Access
• [Journal Article] Near-inertial internal waves and related mixing in the Arctic anticyclonic eddies (2017)
  • Author(s): Eun Yae Son, Yusuke Kawaguchi, Ho-Kyung Ha, Jae-hun Park
  • Journal Title: Proceedings of the 32nd International Symposium on Okhotsk Sea & Sea Ice Volume: -
  • Int'l Joint Research
• [Journal Article] Quantification of the turbulent mixing and associated diapycnal heat transfer (2017)
  • Author(s): Hiroki Takeda, Yusuke Kawaguchi, Jun Inoue, Shigeto Nishino, Michael Steele, Katsuhisa Maeno, Kristina Colburn, Naoki Sato
  • Journal Title: Proceedings of the 32nd International Symposium on Okhotsk Sea & Sea Ice Volume: -
  • Int'l Joint Research
• [Journal Article] Enhanced diapycnal mixing due to near-inertial internal waves propagating through an anticyclonic eddy in the ice-free Chukchi Plateau (2016)
  • Author(s): Yusuke Kawaguchi, Shigeto Nishino, Hiroki Takeda, Inoue Jun, Maeno Katsuhisa, Kazuhiro Oshima
  • Journal Title: Journal of Physical Oceanography Volume: 46 Issue: 8 Pages: 2457-2481
  • DOI: 10.1175/jpo-d-15-0150.1
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Journal Article] Sea-ice melt onset associated with lead opening during the spring/summer transition near the North Pole (2016)
  • Author(s): Vivier Frederic, Hutchings Jennifer, Yusuke Kawaguchi, Kikuchi Takashi, James Morison,Noguchi Tomohide, Lourenco Antonio
  • Journal Title: Journal of Geophysical Research Oceans Volume: 121 Issue: 4 Pages: 2499-2522
  • DOI: 10.1002/2015jc011588
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Coupled response of bacterial production to wind-induced fall phytoplankton bloom and sediment resuspension in the Chukchi sea shelf, western arctic ocean (2016)
  • Author(s): Mario Uchimiya, Chiaki Motegi, Shigeto Nishino, Yusuke Kawaguchi, Jun Inoue, Hiroshi Ogawa, Toshi Nagata
  • Journal Title: Frontiers in Marine Science Volume: 3 Pages: 231-231
  • DOI: 10.3389/fmars.2016.00231
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Journal Article] Enhanced turbulent energy dissipation due to internal wave breaking within an anticyclonic Arctic eddy (2016)
  • Author(s): Yusuke Kawaguchi, Hiroki Takeda, Jun Inoue, Shigeto Nishino, Katsuhiro Maeno
  • Journal Title: Proceedings of the 31st international symposium on Okhotsk Sea & Sea ice Volume: - Pages: 128-130
• [Journal Article] Turbulent mixing within the mixed layer from direct microstructure measurements during Arctic cruise MR14-05 (2016)
  • Author(s): Hiroki Takeda, Yusuke Kawaguchi, Naoki Sato
  • Journal Title: Proceedings of the 31st international symposium on Okhotsk Sea & Sea Ice Volume: - Pages: 138-141
• [Presentation] Seasonal variability of near-inertial internal waves in the Northwind Abyssal Plain, Arctic Ocean (2018)
  • Author(s): Yusuke Kawaguchi
  • Organizer: Fifth International Symposium on Arctic Research, ISAR-5
  • Int'l Joint Research
• [Presentation] Role of anticyclonic eddies in vertical mixing in Canada Basin, Arctic (2017)
  • Author(s): Eun Yae Son, Yusuke Kawaguchi, Jae-hun Park, Ho-Kyung Ha
  • Organizer: Port and Ocean Engineering under Arctic Conditions (POAC) '17
  • Place of Presentation: 韓国、釜山
  • Year and Date: 2017-06-11
• [Presentation] Seasonal variability of near-inertial internal waves and its kinetic energy in the ice-diminishing Arctic Ocean (2017)
  • Author(s): Yusuke Kawaguchi
  • Organizer: JpGU-AGU Joint Meeting 2017
  • Place of Presentation: 千葉県千葉市、幕張メッセ
  • Year and Date: 2017-05-27
  • Int'l Joint Research
• [Presentation] Enhanced diapycnal mixing due to near-inertial internal waves propagating through an anticyclonic eddy in the ice-free Chukchi Plateau (2017)
  • Author(s): Yusuke Kawaguchi
  • Organizer: European Geosciences Union (EGU) 2017 general assembly
  • Place of Presentation: オーストリア、ウィーン
  • Year and Date: 2017-04-27
  • Int'l Joint Research
• [Presentation] Mixing and Vertical Heat Transfer in the Surface Mixed Layer of the Arctic Ocean: Implication of a Cross-Pycnocline High-Temperature Anomaly (2017)
  • Author(s): Yusuke Kawaguchi and Hiroki Takeda
  • Organizer: European Geosciences Union (EGU) 2017 general assembly
  • Place of Presentation: オーストリア、ウィーン
  • Year and Date: 2017-04-27
  • Int'l Joint Research
• [Presentation] Double-diffusion and energetic internal waves observed in Arctic Ocean vortices (2017)
  • Author(s): Yusuke Kawaguchi
  • Organizer: OMIX国際シンポジウム
  • Place of Presentation: 東京都文京区、東京大学
  • Year and Date: 2017-03-17
• [Presentation] 北極海の海氷消失が及ぼす北極海の乱流化現象について (2017)
  • Author(s): 川口悠介、伊東素代、菊地隆、小野寺丈直太朗, 原田直美
  • Organizer: ブルーアース2017
  • Place of Presentation: 東京都千代田区、日本大学理工学部 駿河台キャンパス
  • Year and Date: 2017-03-02
• [Presentation] 北極海バロー沖の低気圧性渦における二重拡散多重貫入構造 (2017)
  • Author(s): 川口悠介,西野茂人、藤原周、竹田大樹
  • Organizer: ブルーアース2017
  • Place of Presentation: 東京都千代田区、日本大学理工学部 駿河台キャンパス
  • Year and Date: 2017-03-02
• [Presentation] 西部北極海における高気圧渦・乱流混合の相互作用についての研究 (2017)
  • Author(s): Eun Yae Son, Yusuke Kawaguchi, Jae Hun Park, Ho Kyung Ha
  • Organizer: The 32nd International symposium on Sea of Okhotsk and Sea Ice
  • Place of Presentation: 北海道紋別市、紋別市文化会館
  • Year and Date: 2017-02-20
  • Int'l Joint Research
• [Presentation] 太平洋側北極海における海洋混合層の乱流混合と鉛直熱輸送の定量的評価 (2017)
  • Author(s): Hiroki Takeda、 Yusuke Kawaguchi、 Jun Inoue、 Shigeto Nishino、 Sato Naoki、 Katsuhisa Maeno, Michael Steel,Kristina Colburn
  • Organizer: The 32nd international symposium on Sea of Okhotsk & Sea Ice
  • Place of Presentation: 北海道紋別市、紋別市文化会館
  • Year and Date: 2017-02-20
  • Int'l Joint Research
• [Presentation] Observational Study of the eddy-wave-turbulence interaction in the Arctic Ocean (2017)
  • Author(s): 川口悠介
  • Organizer: インハ大学極域海洋研究集会
  • Place of Presentation: 韓国、仁川
  • Year and Date: 2017-02-05
  • Int'l Joint Research / Invited
• [Presentation] Enhanced diapycnal mixing due to near-inertial internal waves propagating through an anticyclonic eddy in the ice-free Chukchi Plateau (2016)
  • Author(s): Yusuke Kawaguchi, Shigeto Nishino, Jun Inoue, Hiroki Takeda, Katsuhisa Maeno, Kazuhiro Oshima
  • Organizer: American Geophysical Union (AGU) fall meeting 2016
  • Place of Presentation: アメリカ、サンフランシスコ
  • Year and Date: 2016-12-12
  • Int'l Joint Research
• [Presentation] Enhanced diapycnal mixing due to near-inertial internal waves propagating through an Anticyclonic eddy in the ice-free Chukchi Plateau (2016)
  • Author(s): Yusuke Kawaguchi, Jun Inoue, Shigeto Nishino, Katsuhisa Maeno, Hiroki Takeda, Kazuhiro Oshima
  • Organizer: The seventh symposium on polar science
  • Place of Presentation: 東京都立川市、国立極地研究所
  • Year and Date: 2016-12-01
  • Int'l Joint Research
• [Presentation] Physical oceanography in polar oceans: sea ice dynamics, turbulent mixing, internal waves, and double-diffusion (2016)
  • Author(s): Yusuke Kawaguchi, Hiroyasu Hasumi
  • Organizer: 日本・ノルウェイ共同研究集会 in Bergen
  • Place of Presentation: ノルウェイ、ベルゲン
  • Year and Date: 2016-12-01
  • Int'l Joint Research
• [Presentation] Enhanced diapycnal mixing due to near-inertial internal waves propagating through an anticlyclonic eddy in the ice-free Chukchi Plateau (2016)
  • Author(s): Yusuke Kawaguchi
  • Organizer: The Forum for Arctic Ocean Modeling & Observational Synthesis (FAMOS) meeting 2016
  • Place of Presentation: アメリカウッズホール、ウッズホール海洋研究所
  • Year and Date: 2016-11-03
  • Int'l Joint Research
• [Presentation] Turbulent mixing and heat balance within the surface mixed layer in the Pacific-side Arctic Ocean (2016)
  • Author(s): Hiroki Takeda、 Yusuke Kawaguchi、 Jun Inoue、 Shigeto Nishino、 Sato Naoki、 Katsuhisa Maeno, Michael Steel,Kristina Colburn
  • Organizer: The Forum for Arctic Ocean Modeling & Observational Synthesis (FAMOS) meeting 2016
  • Place of Presentation: アメリカウッズホール、ウッズホール海洋研究所
  • Year and Date: 2016-11-03
  • Int'l Joint Research
• [Presentation] Monitoring of in situ phytoplankton community structure using multi-excitation chlorophyll fluorometer (2016)
  • Author(s): Amane Fujiwara, Shigeto Nishino, Kohei Matsuno, Jonaotaro Onodera, Yusuke Kawaguchi, Toru Hirawake, Koji Suzuki, Jun Inoue, Takashi Kikuchi
  • Organizer: Ocean Optics Conference 2016
  • Place of Presentation: カナダ、ビクトリア
  • Year and Date: 2016-10-27
  • Int'l Joint Research
• [Presentation] 西部北極海の高気圧渦に補足された近慣性内部重力波の破砕II (2016)
  • Author(s): 川口悠介、西野茂人、猪上淳、竹田大樹、前野克尚、大島和裕
  • Organizer: 2016年度日本海洋学会秋季大会
  • Place of Presentation: 鹿児島県鹿児島市、鹿児島大学
  • Year and Date: 2016-09-11
• [Presentation] 北極海の表層混合層における乱流混合の定量化 ―鉛直熱輸送により形成された混合層直下の水温極大 (2016)
  • Author(s): 竹田大樹、川口悠介、猪上淳、西野茂人、前野克尚、佐藤尚毅
  • Organizer: 2016年度日本海洋学会秋季大会
  • Place of Presentation: 鹿児島県鹿児島市、鹿児島大学
  • Year and Date: 2016-09-11
• [Presentation] 北極海バロー沖の低気圧性暖水渦における二重拡散型多重貫入層 (2016)
  • Author(s): 川口悠介、西野茂人、藤原周、竹田大樹、伊東素代、奥村慎也、徳長航
  • Organizer: 2016年度日本海洋学会秋季大会
  • Place of Presentation: 鹿児島県鹿児島市、鹿児島大学
  • Year and Date: 2016-09-01
• [Presentation] Turbulence and internal waves in the Arctic Ocean (2016)
  • Author(s): Yusuke Kawaguchi
  • Organizer: 日露共同研究集会 in P.P. Shirshov
  • Place of Presentation: ロシア、モスクワ
  • Year and Date: 2016-08-01
  • Int'l Joint Research
• [Presentation] Enhanced diapycnal mixing due to near-inertial internal waves propagating through an anticlyclonic eddy in the ice-free Chukchi Plateau (2016)
  • Author(s): Yusuke Kawaguchi
  • Organizer: The 22nd international Symposium on Polar Sciences
  • Place of Presentation: 韓国、仁川 Korea Polar Research Institute
  • Year and Date: 2016-05-10
  • Int'l Joint Research