• Search Research Projects
  • Search Researchers
  • How to Use
  1. Back to previous page

Global mapping of diapycnal mixing rates in the deep ocean

Research Project

Project/Area Number 14340136
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Meteorology/Physical oceanography/Hydrology
Research InstitutionThe University of Tokyo

Principal Investigator

HIBIYA Toshiyuki  The University of Tokyo, Graduate School of Science, Professor, 大学院・理学系研究科, 教授 (80192714)

Co-Investigator(Kenkyū-buntansha) HASUMI Hiroyasu  The University of Tokyo, Center of Climate System Research, Research Associate, 気候システム研究センター, 助手 (40311641)
ISODA Yutaka  Hokkaido University, Faculty of Fisheries, Associate Professor, 大学院・水産科学研究科, 助教授 (10193393)
YOSHIDA Jiro  Tokyo University of Marine Science and Technology, Faculty of Marine Science, Professor, 海洋科学部, 教授 (30174931)
Project Period (FY) 2002 – 2003
Project Status Completed (Fiscal Year 2003)
Budget Amount *help
¥16,900,000 (Direct Cost: ¥16,900,000)
Fiscal Year 2003: ¥6,100,000 (Direct Cost: ¥6,100,000)
Fiscal Year 2002: ¥10,800,000 (Direct Cost: ¥10,800,000)
KeywordsDiapycnal mixing / Latitudinal dependence / Global thermohaline circulation model / Semidiurnal internal tides / Parametric subharmonic instability / Energy cascade / Near inertial current shear / Expendable current profiler / 投棄式流速計 / 乱流拡散 / 海洋深層 / 流速シアー / パラメタリゼーション / 慣性周波数
Research Abstract

Global mapping of diapycnal mixing rates in the thermocline is essential to improve the ability of global thermohaline circulation models in predicting future climate changes. For this purpose, we have first estimated diapycnal mixing rates over a large area in the interior of the North and South Pacific, the North Atlantic and the South Indian Ocean by incorporating the fine-scale vertical shear of horizontal velocity measured by expendable current profilers (XCP) into Gregg's formula (Gregg, 1989). The remarkable finding from the XCP survey is that the estimated diapycnal mixing rate in the thermocline is strongly dependent on the latitude.
Then, these estimates have been related to the main energy source for diapycnal mixing, the semidiumal internal tide energy numerically calculated at each location, and an empirical formula has been found to predict the global distribution of diapycnal mixing rates in the deep ocean. Incorporating the numerically predicted semidiurnal internal tide energy at each longitude and latitude into the resulting empirical formula, we have found that strong diapycnal mixing (mixing hotspot) is limited to prominent topographic features at latitudes 20^0 -30^0 where the available semidiurnal internal tide energy can be efficiently transferred to dissipation scales by resonant interactions amongst internal waves called parametric subharmonic instability.
Embedding the obtained distribution of diapycnal mixing rates into global thermohaline circulation models should yield significant improvement in their ability to predict future climate change.

Report

(3 results)
  • 2003 Annual Research Report   Final Research Report Summary
  • 2002 Annual Research Report
  • Research Products

    (35 results)

All Other

All Publications (35 results)

  • [Publications] Hibiya, T., M.Nagasawa, Y.Niwa: "Nonlinear energy transfer within the oceanic internal wave spectrum at mid and high latitudes"Journal of Geophysical Research. 107・C11. 3207, doi:10.1029/2001JC001210 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Nagasawa, M., T.Hibiya, Y.Niwa, M.Watanabe, Y.Isoda, S.Takagi, Y.Kamei: "Distribution of fine-scale shear in the deep waters of the North Pacific obtained using expendable current profilers"Journal of Geophysical Research. 107・C12. 3221, doi:10.1029/2002JC001376 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Watanabe, M., T.Hibiya: "Global estimates of the wind-induced energy flux to inertial motions in the surface mixed layer"Geophysical Research Letters. 29・8. 1239, 10.1029/2001GL014422 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Katsumata, K., T.Hibiya: "Internal wave generation by tidal flow over a sill in a rotating channel"Journal of Geophysical Research. 107・C10. 3176, doi:10.1029/2001JC001096 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Katsumata, K., T.Hibiya: "Frictionless generation of a tidal eulerian residual flow over a sill in a narrow channel"Journal of Oceanography. 59・3. 325-329 (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Hibiya, T.M.Nagasawa: "Latitudinal dependence of diapycnal diffusivity in the thermocline using a finescale parameterization"Geophysical Research Letters. 31・1. L01301, doi:10.1029/2003GL017998 (2004)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Hibiya, T.: "Internal wave generation by tidal flow over a continental shelf slope"Journal of Oceanography. 60・3. 637-643 (2004)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Niwa, Y., T.Hibiya: "Three-dimensional numerical simulation of M_2 internal tides in the East China Sea"Journal of Geophysical Research. 109. C04027, doi:10.1029/2003JC001923 (2004)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Watanabe, M., T.Hibiya: "Estimates of energy dissipation rates in the three-dimensional deep ocean internal wave field"Journal of Oceanography. (in press). (2004)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Yoshida, J., H.Nagashima: "Numerical experiments on salt finger convection"Progress in Oceanography. 56・3. 435-459 (2004)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Komuro, Y., H.Hasumi: "Effects of surface freshwater flux induced by sea ice transport on the global thermohaline circulation"Journal of Geophysical Research. 108・C2. 3047, doi:10.1029/2002JC001476 (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Komuro, Y., H.Hasumi: "Sensitivity of the global thermohaline circulation to interbasin freshwater transport by the atmosphere and the Bering Strait throughflow"Journal of Climate. 15・17. 2516-2526 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Hibiya, T., M.Nagasawa, Y.Niwa: "Nonlinear energy transfer within the oceanic internal wave spectrum at mid and high latitudes"Journal of Geophysical Research. 107・C11. 3207,doi:10.1029/2002JC001210 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Nagasawa, M., T.Hibiya, Y.Niwa, M.Watanabe, Y.Isoda, S.Takagi, Y.Kamei: "Distribution of fine-scale shear in the deep waters of the North Pacific obtained using expendable current profilers"Journal of Geophysical Research. 107・C12. 3221,doi:10.1029/2002JC001376 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Watanabe, M., T.Hibiya: "Global estimates of the wind-induced energy flux to inertial motions in the surface mixed layer"Geophysical Research Letters. 29・8. 1239,10.1029/2001GL014422 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Katsumata, K., T.Hibiya: "Internal wave generation by tidal flow over a sill in a rotating channel"Journal of Geophysical Research. 107・C10. 3176,doi:10.1029/2001JC001096 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Katsumata, K., T.Hibiya: "Frictionless generation of a tidal eulerian residual flow over a sill in a narrow channel"Journal of Oceanography. 59・3. 325-329 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Hibiya, T., M.Nagasawa: "Latitudinal dependence of diapycnal diffusivity in the thermocline using a finescale parameterization"Geophysical Research Letters. 31・1. L01301,doi:10.1029/2003GL017998 (2004)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Hibiya, T.: "Internal wave generation by tidal flow over a continental shelf slope"Journal of Oceanography. 60・3. 637-643 (2004)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Niwa, Y., T.Hibiya: "Three-dimensional numerical simulation of M_2 internal tides in the East China Sea"Journal of Geophysical Research. 109・C04027. doi:10.1029/2003JC001923 (2004)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Watanabe, M., T.Hibiya: "Estimates of energy dissipation rates in the three-dimensional deep ocean internal wave field"Journal of Oceanography. (In press). (2004)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Yoshida, J., H.Nagashima: "Numerical experiments on salt finger convection"Progress in Oceanography. 56・3. 435-459 (2004)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Komuro, Y., H.Hasumi: "Effects of surface freshwater flux induced by sea ice transport on the global thermohaline circulation"Journal of Geophysical Research. 108・C2. 3047,doi:10.1029/2002JC001476 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Komuro, Y., H.Hasumi: "Sensitivity of the global thermohaline circulation to interbasin freshwater transport by the atmosphere and the Bering Strait throughflow"Journal of Climate. 15・17. 2516-2526 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Hibiya, T., M.Nagasawa: "Latitudinal dependence of diapycnal diffusivity in the thermocline using a finescale parameterization"Geophysical Research Letters. 31・1. L01301,doi:10.1029/2003GL017998 (2004)

    • Related Report
      2003 Annual Research Report
  • [Publications] Hibiya, T.: "Internal wave generation by tidal flow over a continental shelf slope"Journal of Oceanography. (In press). (2004)

    • Related Report
      2003 Annual Research Report
  • [Publications] Niwa, Y., T.Hibiya: "Three-dimensional numerical simulation of M_2 internal tides in the East China Sea"Journal of Geophysical Research. (In press). (2004)

    • Related Report
      2003 Annual Research Report
  • [Publications] Katsumata, K., T.Hibiya: "Frictionless generation of a tidal Eulerian residual flow over a sill in a narrow channel"Journal of Oceanography. 59・3. 325-329 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] Yoshida, J., H.Nagashima: "Numerical experiments on salt finger convection"Progress in Oceanography. 56・3. 435-459 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] Komuro, Y., H.Hasumi: "Effects of surface freshwater flux induced by sea ice transport on the global thermohaline circulation"Journal of Geophysical Research. 108・C2. 3047,doi:10.1029/2002JC001476 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] Hibiya, T., M.Nagasawa, Y.Niwa: "Nonlinear energy transfer within the oceanic internal wave spectrum at mid and high latitudes"Journal of Geophysical Research. 107・C11. Art.No.-3207 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] Nagasawa, M., T.Hibiya, Y.Niwa, M.Watanabe, Y.Isoda, S.Takagi, Y.Kamei: "Distribution of fine-scale shear in the deep waters of the North Pacific obtained using expendable current profilers"Journal of Geophysical Research. 107・C12. Art.No.-3221 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] Katsumata, K., T.Hibiya: "Internal wave generation by tidal flow over a sill in a rotating channel"Journal of Geophysical Research. 107・C10. Art.No.-3176 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] Watanabe, M., T.Hibiya: "Global estimates of the wind-induced energy flux to inertial motions in the surface mixed layer"Geophysical Research Letters. 29・8. Art.No.-1239 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] Katsumata, K., T.Hibiya: "Frictionless generation of a tidal eulerian residual flow over a sill in a narrow channel"Journal of Oceanography. 59・3(in press). (2003)

    • Related Report
      2002 Annual Research Report

URL: 

Published: 2002-04-01   Modified: 2016-04-21  

Information User Guide FAQ News Terms of Use Attribution of KAKENHI

Powered by NII kakenhi