Unified understanding of ocean mixing processes and impacts

2019 Fiscal Year Annual Research Report

• Project Area: Ocean Mixing Processes: Impact on Biogeochemistry, Climate and Ecosystem
• Project/Area Number: 15H05817
• Research Institution: The University of Tokyo
• Principal Investigator: 安田 一郎 東京大学, 大気海洋研究所, 教授 (80270792)
• Co-Investigator(Kenkyū-buntansha): 増田 周平 国立研究開発法人海洋研究開発機構, 地球環境部門(海洋観測研究センター), センター長 (30358767) ; 西岡 純 北海道大学, 低温科学研究所, 准教授 (90371533) ; 郭 新宇 愛媛大学, 沿岸環境科学研究センター, 教授 (10322273) ; 原田 尚美 国立研究開発法人海洋研究開発機構, 地球環境部門(地球表層システム研究センター), センター長 (70344281) ; 伊藤 進一 東京大学, 大気海洋研究所, 教授 (00371790) ; 日比谷 紀之 東京大学, 大学院理学系研究科(理学部), 教授 (80192714) ; 羽角 博康 東京大学, 大気海洋研究所, 教授 (40311641)
• Project Period (FY): 2015-06-29 – 2020-03-31
• Keywords: 海洋混合学 / 鉛直混合 / 海洋物質循環 / 海洋生態系 / 気候変動 / 潮汐 / 乱流 / 海洋循環

Outline of Annual Research Achievements

実態が不明であった海洋の鉛直混合と物質輸送について、深層まで容易に実測できる新しい観測手法やデータ統合システムが開発され、従来に比べて圧倒的に多数の、隣国海域を含む現場観測が行われた。現場観測に基づく分布・輸送から、潮汐によって躍層や複雑な海底地形上で強化される混合分布を組み込んだシミュレーションモデルが開発され、鉛直混合が海洋循環・気候・生態系に与える役割が評価された。北太平洋で従来想定されていたよりも弱い混合に伴う深層循環によって高い密度を維持した水塊が南極周辺で湧昇し海氷分布を変えることで、気候・温暖化速度に影響するとともに、北太平洋中深層に栄養塩が蓄積される。この栄養塩はアリューシャン・千島・伊豆海嶺等で強化された潮汐混合によって中表層に湧昇し、縁辺海に供給される陸起源の鉄とともに、親潮で輸送され、北西太平洋での高い生物生産（海の恵み）を維持する役割を持つ。この水塊は北太平洋の中層循環で亜熱帯・黒潮海域にも輸送され、黒潮が海峡部の浅瀬を横切る際に発生する強烈な鉛直混合によって硝酸塩が表層へ輸送され、生物生産を活発化させる等、黒潮は従来考えられていた貧栄養海域とは異なることが明らかかにされた。強い混合が存在する伊豆諸島海域の低温環境で産卵し、高温の黒潮で輸送される成長の良いマサバ仔魚は、餌の豊富な低温の親潮へ回遊し、さらに成長が促進される。北太平洋規模の水温や水産資源の長期変動の主要な要因である太平洋10年規模振動に、潮汐の18.6年振動の影響が東北沖の海面水温とアリューシャン低気圧の相互作用を通じて増幅し現れることが、混合変動を組み込んだ新しい気候モデルで再現された。本領域で得られた、観測・モデリング手法、データ・理論や研究連携・国際拠点は、新たな課題とともに、新しい研究領域「海洋混合学」として、地球規模の環境変動研究に挑む次世代の研究者に引き継がれる。

Research Progress Status

令和元年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

令和元年度が最終年度であるため、記入しない。

Research Products

• [Int'l Joint Research] ワシントン大学/スクリプス海洋研究所/ウッズホール海洋研究所(米国)
  • Country Name: U.S.A.
  • Counterpart Institution: ワシントン大学/スクリプス海洋研究所/ウッズホール海洋研究所
  • # of Other Institutions: 3
• [Int'l Joint Research] 海洋研究所(韓国)
  • Country Name: KOREA (REP. OF KOREA)
  • Counterpart Institution: 海洋研究所
• [Int'l Joint Research] 極東水文気象研究所(ロシア連邦)
  • Country Name: RUSSIA FEDERATION
  • Counterpart Institution: 極東水文気象研究所
• [Int'l Joint Research] 青島海洋大学(中国)
  • Country Name: CHINA
  • Counterpart Institution: 青島海洋大学
• [Int'l Joint Research] BBBP(インドネシア)
  • Country Name: INDONESIA
  • Counterpart Institution: BBBP
• [Int'l Joint Research]
  • # of Other Countries: 5
• [Journal Article] Cold Water Upwelling Near the Anadyr Strait: Observations and Simulations (2020)
  • Author(s): Kawaguchi Yusuke、Nishioka Jun、Nishino Shigeto、Fujio Shinzou、Lee Keunjong、Fujiwara Amane、Yanagimoto Daigo、Mitsudera Humio、Yasuda Ichiro
  • Journal Title: Journal of Geophysical Research: Oceans Volume: 125 Pages: -
  • DOI: 10.1029/2020JC016238
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Determining subsurface oceanic changes in the Indian sector of the Southern Ocean using Argo float data (2020)
  • Author(s): Masuda Shuhei
  • Journal Title: Polar Science Volume: 23 Pages: 100498～100498
  • DOI: 10.1016/j.polar.2019.100498
  • Peer Reviewed / Open Access
• [Journal Article] Subpolar marginal seas fuel the North Pacific through the intermediate water at the termination of the global ocean circulation (2020)
  • Author(s): Nishioka Jun、Obata Hajime、Ogawa Hiroshi、Ono Kazuya、Yamashita Youhei、Lee Keunjong、Takeda Shigenobu、Yasuda Ichiro
  • Journal Title: Proceedings of the National Academy of Sciences Volume: 117 Pages: 12665～12673
  • DOI: 10.1073/pnas.2000658117
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Shelf humic substances as carriers for basin-scale iron transport in the North Pacific (2020)
  • Author(s): Yamashita Youhei、Nishioka Jun、Obata Hajime、Ogawa Hiroshi
  • Journal Title: Scientific Reports Volume: 10 Pages: -
  • DOI: 10.1038/s41598-020-61375-7
  • Peer Reviewed / Open Access
• [Journal Article] Metabolic measurements and parameter estimations for bioenergetics modelling of Pacific Chub Mackerel Scomber japonicus (2020)
  • Author(s): Guo Chenying、Ito Shin‐ichi、Wegner Nicholas C.、Frank Laura N.、Dorval Emmanis、Dickson Kathryn A.、Klinger Dane H.
  • Journal Title: Fisheries Oceanography Volume: 29 Pages: 215～226
  • DOI: 10.1111/fog.12465
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Temperature dependency equation for chub mackerel (Scomber japonicus) identified by a laboratory rearing experiment and microscale analysis (2020)
  • Author(s): Nakamura Masahiro、Yoneda Michio、Ishimura Toyoho、Shirai Kotaro、Tamamura Masaki、Nishida Kozue
  • Journal Title: Marine and Freshwater Research Volume: 71 Pages: 1384～1384
  • DOI: 10.1071/MF19313
  • Peer Reviewed
• [Journal Article] Control of transient climate response and associated sea level rise by deep-ocean mixing (2020)
  • Author(s): Watanabe Michio、Tatebe Hiroaki、Suzuki Tatsuo、Tachiiri Kaoru
  • Journal Title: Environmental Research Letters Volume: 15 Pages: 094001～094001
  • DOI: 10.1088/1748-9326/ab8ca7
  • Peer Reviewed / Open Access
• [Journal Article] The oceanic sink for anthropogenic CO2from 1994 to 2007 (2019)
  • Author(s): Gruber Nicolas、Clement Dominic、Carter Brendan R.、Feely Richard A.、van Heuven Steven、Hoppema Mario、Ishii Masao、Key Robert M.、Kozyr Alex、Lauvset Siv K.、Lo Monaco Claire、Mathis Jeremy T.、Murata Akihiko、Olsen Are、Perez Fiz F.、Sabine Christopher L.、Tanhua Toste、Wanninkhof Rik
  • Journal Title: Science Volume: 363 Pages: 1193～1199
  • DOI: 10.1126/science.aau5153
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Impacts of Mesoscale Eddies on Phytoplankton Size Structure (2019)
  • Author(s): Waga Hisatomo、Hirawake Toru、Ueno Hiromichi
  • Journal Title: Geophysical Research Letters Volume: 46 Pages: 13191～13198
  • DOI: 10.1029/2019GL085150
  • Peer Reviewed / Open Access
• [Journal Article] Poleward-propagating near-inertial waves enabled by the western boundary current (2019)
  • Author(s): Jeon Chanhyung、Park Jae-Hun、Nakamura Hirohiko、Nishina Ayako、Zhu Xiao-Hua、Kim Dong Guk、Min Hong Sik、Kang Sok Kuh、Na Hanna、Hirose Naoki
  • Journal Title: Scientific Reports Volume: 9 Pages: -
  • DOI: 10.1038/s41598-019-46364-9
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Tempo‐Spatial Variations of the Kuroshio Current in the Tokara Strait Based on Long‐Term Ferryboat ADCP Data (2019)
  • Author(s): Liu Zhao‐Jun、Nakamura Hirohiko、Zhu Xiao‐Hua、Nishina Ayako、Guo Xinyu、Dong Menghong
  • Journal Title: Journal of Geophysical Research: Oceans Volume: 124 Pages: 6030～6049
  • DOI: 10.1029/2018JC014771
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] How the Kuroshio Current Delivers Nutrients to Sunlit Layers on the Continental Shelves With Aid of Near‐Inertial Waves and Turbulence (2019)
  • Author(s): Nagai Takeyoshi、Durn Gloria Silvana、Otero Diego Andr、Mori Yasutaka、Yoshie Naoki、Ohgi Kazuki、Hasegawa Daisuke、Nishina Ayako、Kobari Toru
  • Journal Title: Geophysical Research Letters Volume: 46 Pages: 6726～6735
  • DOI: 10.1029/2019GL082680
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Phytoplankton productivity and rapid trophic transfer tomicrozooplankton stimulated by turbulent nitrate flux inoligotrophic Kuroshio Current (2019)
  • Author(s): Kobari Toru、Honma Taiga、Hasegawa Daisuke、Yoshie Naoki、Tsutumi Eisuke、Matsuno Takeshi、Nagai Takeyoshi、Kanayama Takeru、Karu Fukutaro、Suzuki Koji、Tanaka Takahiro、Guo Xinyu、Kume Gen、Nishina Ayako、Nakamura Hirohiko
  • Journal Title: Biogeosciences Volume: 17 Pages: -
  • DOI: 10.5194/bg-2019-377
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Eukaryotic Phytoplankton Contributing to a Seasonal Bloom and Carbon Export Revealed by Tracking Sequence Variants in the Western North Pacific (2019)
  • Author(s): Shiozaki Takuhei、Hirose Yuu、Hamasaki Koji、Kaneko Ryo、Ishikawa Kazuo、Harada Naomi
  • Journal Title: Frontiers in Microbiology Volume: 10 Pages: -
  • DOI: 10.3389/fmicb.2019.02722
  • Peer Reviewed / Open Access
• [Journal Article] Otolith oxygen isotope analysis and temperature history in early life stages of the chub mackerel Scomber japonicus in the Kuroshio: Oyashio transition region (2019)
  • Author(s): Higuchi Tomihiko、Ito Shin-ichi、Ishimura Toyoho、Kamimura Yasuhiro、Shirai Kotaro、Shindo Hana、Nishida Kozue、Komatsu Kosei
  • Journal Title: Deep Sea Research Part II: Topical Studies in Oceanography Volume: 169-170 Pages: 104660～104660
  • DOI: 10.1016/j.dsr2.2019.104660
  • Peer Reviewed
• [Journal Article] Assessment of Finescale Parameterizations of Deep Ocean Mixing in the Presence of Geostrophic Current Shear: Results of Microstructure Measurements in the Antarctic Circumpolar Current Region (2019)
  • Author(s): Takahashi Anne、Hibiya Toshiyuki
  • Journal Title: Journal of Geophysical Research: Oceans Volume: 124 Pages: 135～153
  • DOI: 10.1029/2018JC014030
  • Peer Reviewed / Open Access
• [Journal Article] Quasi-local method of wave decomposition in a slowly varying medium (2019)
  • Author(s): Onuki Yohei
  • Journal Title: Journal of Fluid Mechanics Volume: 883 Pages: -
  • DOI: 10.1017/jfm.2019.825
  • Peer Reviewed / Open Access
• [Journal Article] Instabilities of Finite‐Amplitude Internal Wave Beams (2019)
  • Author(s): Onuki Y.、Tanaka Y.
  • Journal Title: Geophysical Research Letters Volume: 46 Pages: 7527～7535
  • DOI: 10.1029/2019GL082570
  • Peer Reviewed / Open Access
• [Presentation] Vertical mixing intensified around sea mounts in the Kuroshio (2020)
  • Author(s): Matsuno, T., E. Tsutsumi, T. Senjyu, T. Endoh, D. Hasegawa , Y. J. Yang, S. Jan, H. Nakamura, X. Guo, I. Yasuda
  • Organizer: The 16th Japan-Korea Joint Seminar on Ocean Sciences
  • Int'l Joint Research / Invited
• [Presentation] Micro- and macro-nutrient supply from the marginal seas to the North Pacific Ocean and its changing (2019)
  • Author(s): Nishioka, J., H. Obata, I. Yasuda
  • Organizer: PICES annual meeting 2019
  • Int'l Joint Research / Invited
• [Presentation] Change in lower trophic level ecosystem and its complex mechanism in the North Pacific. (2019)
  • Author(s): Harada N., T. Fujiki, M. Aita, M. Honda, M. Kitamura, T. Shiozaki, Y. Mino, A. Kuwata, K. Tadokoro, O. Seki, M. Chikamoto
  • Organizer: JpGU2019
  • Int'l Joint Research / Invited
• [Presentation] Climate Change and Fish Production in the Pacific (2019)
  • Author(s): Ito Shin-Ichi
  • Organizer: International Conference on Climate Change and Fragility in the Asia-Pacific Region 2019 - Climate Change and the Pacific Ocean -
  • Int'l Joint Research / Invited
• [Remarks] 海洋混合学の創設「物質循環・気候・生態系の維持と長周期変動の解明」
  • URL: http://omix.aori.u-tokyo.ac.jp
• [Remarks] OMIX国際活動報告
  • URL: http://omix.aori.u-tokyo.ac.jp/international-activity/
• [Remarks] OMIX研究成果報告
  • URL: http://omix.aori.u-tokyo.ac.jp/achievements/
• [Remarks] OMIXニュースレター
  • URL: http://omix.aori.u-tokyo.ac.jp/news_letter/
• [Remarks] OMIX一般の方々へ
  • URL: http://omix.aori.u-tokyo.ac.jp/
• [Funded Workshop] Workshop on turbulent mixing in the Kuroshio current over the topography, コンビーナ 遠藤貴洋, Sen Jan, 2020年2月1日, 福岡 (2020)
• [Funded Workshop] Ocean Science Meeting 2020, AGU, “Defining the new frontiers of ocean mixing research”, Toshiyuki Hibiya, Hidekatsu Yamazaki, Gregory N. Ivey, Naomi Harada (2020)
• [Funded Workshop] Ocean Science Meeting 2020, “Defining the New Frontiers of Ocean Mixing Research; Posters”, AGU・ASLO・TOS, February 16-21, 2020, San Diego Convention Center, San Diego, California, U.S.A. (2020)
• [Funded Workshop] SOLAS Open Science Conference, 21 April to 25 April, 2019, Hokkaido University in Sapporo (2019)
• [Funded Workshop] SOLAS Science Steering Committee meeting, from 26 April to 28 April, 2019, Sapporo (2019)
• [Funded Workshop] 2019 IMBeR Open Science Conference, セッション開催、セッション名Biogeochemical and biological processes promoted by ocean mixing”を開催、2019年6月19日 (2019)
• [Funded Workshop] The third workshop of WESTPAC WG06 on “A framework for cooperative studies in the Western Pacific Marginal Seas : Energy and materials exchange between land and open ocean”, 10-11 June 2019, Seoul (2019)
• [Funded Workshop] 2019 SCOR Annual meeting，大会委員長 張 勁, 23-25 September 2019, Toyama (2019)
• [Funded Workshop] 富山県・ SCOR 共催シンポジウム「増ええる海洋環境への脅威と対応 海洋ごみの今とその先へ」 (2019)
• [Funded Workshop] Biogeochemistry of trace elements and isotopes in the ocean; from GEOSECS to GEOTRACES (SCOR-GEOTRACES Joint English Session), 日本海洋学会2019年秋季大会 (2019)
• [Funded Workshop] JpGU Meeting 2019・A-OS08 (ECS-Kuroshio and Ryukyu Current System -Observation, modeling and theory-), 日本地球惑星科学連合, 2019年5月29日, 千葉県幕張メッセ (2019)
• [Funded Workshop] The Future Oceans2, Integrated Marine Biosphere Research project, “Biogeochemical and biological processes promoted by ocean mixing”, Jun 20th, 2019, Le Quartz Congress Centre, Brest, France (2019)
• [Funded Workshop] JpGU-;AGU Joint Session A-OS09：”Marine ecosystems and biogeochemical, cycles: theory, observation and modeling”、JpGU、2019年5月27日、幕張メッセ (2019)
• [Funded Workshop] S5 “Trends in ocean and coastal ecosystems and their services and its future”、PICES、2019年10月22-23日、Victoria International Conference Center, Canada (2019)
• [Funded Workshop] 27th International Union of Geodesy and Geophysics (IUGG) General Assembly, “Mixing Processes in the Ocean”, IUGG, July 8-18, 2019, Montreal Convention Center, Montreal, Canada (2019)