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The role of mesoscale eddies as a possible energy source for diapycnal mixing in the deep ocean maintaining the global overturning circulation

Research Project

Project/Area Number 25800260
Research Category

Grant-in-Aid for Young Scientists (B)

Allocation TypeMulti-year Fund
Research Field Meteorology/Physical oceanography/Hydrology
Research InstitutionThe University of Tokyo

Principal Investigator

Tanaka Yuki  東京大学, 大学院理学系研究科(理学部), 助教 (80632380)

Project Period (FY) 2013-04-01 – 2017-03-31
Project Status Completed (Fiscal Year 2016)
Budget Amount *help
¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000)
Fiscal Year 2015: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2014: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2013: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Keywords鉛直乱流混合 / エネルギーフラックス / 内部波 / 風下波 / 熱帯不安定波 / 赤道太平洋 / 渦解像海洋大循環モデル / 黒潮大蛇行 / 膠州海山 / 傾圧不安定 / 地形性捕捉波 / 二層準地衡流モデル / 線形安定性解析 / 黒潮 / 蛇行 / 海底地形 / 深層海洋大循環 / 地衡流 / 黒潮続流 / 全球渦解像海洋大循環モデル
Outline of Final Research Achievements

Turbulent mixing in the thermocline of the equatorial Pacific Ocean is an important process that controls diapycnal heat transport and affects the global climate. In this study, using an eddy-resolving ocean general circulation model, we show that tropical instability waves (TIWs), propagating westward at a speed of ~0.5 m s-1 with a wavelength of ~1000 km, play an important role in inducing turbulent mixing. The front of the TIW is clearly manifested as a narrow strip of strong convergence of horizontal surface flow, from which area downward propagating internal waves are intermittently radiated. These internal waves can be interpreted as lee waves generated by the surface-flow convergence zone, which acts like an inverted obstacle moving along the ocean surface. The associated downward energy flux integrated over the entire equatorial Pacific averaged during January 2011 amounts to ~8.1 GW, creating an energy pathway to turbulent mixing in the thermocline of the equatorial Pacific.

Report

(5 results)
  • 2016 Annual Research Report   Final Research Report ( PDF )
  • 2015 Research-status Report
  • 2014 Research-status Report
  • 2013 Research-status Report
  • Research Products

    (15 results)

All 2017 2016 2015 2014 Other

All Journal Article (2 results) (of which Peer Reviewed: 2 results,  Acknowledgement Compliant: 1 results) Presentation (13 results) (of which Int'l Joint Research: 4 results)

  • [Journal Article] Downward lee wave radiation from tropical instability waves in the central equatorial Pacific Ocean: a possible energy pathway to turbulent mixing2015

    • Author(s)
      Tanaka, Y., T. Hibiya, and H. Sasaki
    • Journal Title

      Journal of Geophysical Research-Oceans

      Volume: 120 Issue: 11 Pages: 7137-7149

    • DOI

      10.1002/2015jc011017

    • Related Report
      2015 Research-status Report
    • Peer Reviewed / Acknowledgement Compliant
  • [Journal Article] Internal tides and turbulent mixing observed in the Bussol Strait2014

    • Author(s)
      Tanaka, Y., I. Yasuda, S. Osafune, T. Tanaka, J. Nishioka, and Y. N. Volkov
    • Journal Title

      Progress in Oceanography

      Volume: 126 Pages: 98-108

    • DOI

      10.1016/j.pocean.2014.04.009

    • Related Report
      2014 Research-status Report
    • Peer Reviewed
  • [Presentation] Effects of Koshu Seamount on the development of baroclinic instability leading to the Kuroshio large meander2017

    • Author(s)
      Tanaka, Y., and T. Hibiya
    • Organizer
      Asia Oceania Geosciences Society (AOGS) 14th Annual Meeting
    • Place of Presentation
      シンガポール(シンガポール)
    • Related Report
      2016 Annual Research Report
    • Int'l Joint Research
  • [Presentation] 黒潮大蛇行を引き起こす傾圧不安定の発達に膠州海山が果たす役割2017

    • Author(s)
      田中祐希, 日比谷紀之
    • Organizer
      日本地球惑星科学連合-アメリカ地球物理学連合合同2017年大会
    • Place of Presentation
      幕張メッセ(千葉県千葉市)
    • Related Report
      2016 Annual Research Report
  • [Presentation] 太平洋の熱帯不安定波から下向きに放射される風下波 -表層下の乱流混合過程へのエネルギー輸送-2016

    • Author(s)
      田中祐希、日比谷紀之、佐々木英治
    • Organizer
      日本地球惑星科学連合2016年大会
    • Place of Presentation
      幕張メッセ(千葉県千葉市)
    • Year and Date
      2016-05-22
    • Related Report
      2015 Research-status Report
  • [Presentation] Downward lee wave radiation from tropical instability waves in the central equatorial Pacific Ocean: a possible energy pathway to turbulent mixing2016

    • Author(s)
      Tanaka, Y., T. Hibiya, and H. Sasaki
    • Organizer
      2016 Ocean Sciences Meeting
    • Place of Presentation
      New Orleans (USA)
    • Year and Date
      2016-02-24
    • Related Report
      2015 Research-status Report
    • Int'l Joint Research
  • [Presentation] 黒潮大蛇行を引き起こす傾圧不安定の発達に膠州海山が果たす役割2016

    • Author(s)
      田中祐希, 日比谷紀之
    • Organizer
      日本地球惑星科学連合2016年大会
    • Place of Presentation
      幕張メッセ(千葉県千葉市)
    • Related Report
      2016 Annual Research Report 2015 Research-status Report
  • [Presentation] Downward lee wave radiation from Pacific tropical instability waves: A possible energy pathway to turbulent mixing2016

    • Author(s)
      Tanaka, Y., T. Hibiya, and H. Sasaki
    • Organizer
      Japan Geoscience Union Meeting 2016
    • Place of Presentation
      幕張メッセ(千葉県千葉市)
    • Related Report
      2016 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Downward “lee wave” radiation from tropical instability waves in the central equatorial Pacific: a possible energy pathway to turbulent mixing2015

    • Author(s)
      Tanaka, Y., T. Hibiya, and H. Sasaki
    • Organizer
      26th International Union of Geodesy and Geophysics (IUGG) General Assembly
    • Place of Presentation
      Prague (Czech Republic)
    • Year and Date
      2015-07-01
    • Related Report
      2015 Research-status Report
    • Int'l Joint Research
  • [Presentation] Downward “lee wave” radiation from tropical instability waves in the central equatorial Pacific: a possible energy pathway to turbulent mixing2015

    • Author(s)
      Tanaka, Y., T. Hibiya, and H. Sasaki
    • Organizer
      International Union of Geodesy and Geophysics
    • Place of Presentation
      プラハコングレスセンター(チェコ)
    • Year and Date
      2015-07-01
    • Related Report
      2014 Research-status Report
  • [Presentation] 太平洋赤道域の熱帯不安定波から励起される内部波 -高解像度OGCMの結果から-2015

    • Author(s)
      田中祐希, 日比谷紀之, 佐々木英治
    • Organizer
      2015年度日本海洋学会春季大会
    • Place of Presentation
      東京海洋大学品川キャンパス(東京都)
    • Year and Date
      2015-03-24
    • Related Report
      2014 Research-status Report
  • [Presentation] 高解像度OGCMで見られる太平洋赤道域の内部波2014

    • Author(s)
      田中祐希, 日比谷紀之, 佐々木英治
    • Organizer
      2014年度海洋乱流研究会
    • Place of Presentation
      京都大学吉田キャンパス(京都府)
    • Year and Date
      2014-12-23
    • Related Report
      2014 Research-status Report
  • [Presentation] Internal Tides and Turbulent Mixing Observed in the Bussol Strait

    • Author(s)
      Tanaka, Y., I. Yasuda, S. Osafune, T. Tanaka, J. Nishioka, and Y. N. Volkov
    • Organizer
      Asia Oceania Geosciences Society 10th Annual Meeting
    • Place of Presentation
      Brisbane Convention & Exhibition Centre, Brisbane, Australia
    • Related Report
      2013 Research-status Report
  • [Presentation] Global estimates of internal wave energy flux radiating from geostrophic flows

    • Author(s)
      Tanaka, Y., T. Hibiya, and H. Sasaki
    • Organizer
      Ocean Sciences Meeting 2014
    • Place of Presentation
      Hawaii Convention Center, Honolulu, Hawaii, USA
    • Related Report
      2013 Research-status Report
  • [Presentation] 渦解像海洋大循環モデルによる地衡流起源内部波エネルギーの全球的見積もり

    • Author(s)
      田中祐希, 日比谷紀之, 佐々木英治
    • Organizer
      2014年度日本海洋学会春季大会
    • Place of Presentation
      東京海洋大学品川キャンパス(東京)
    • Related Report
      2013 Research-status Report

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Published: 2014-07-25   Modified: 2019-07-29  

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