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The Effect of Double Diffusive Convention in the Mixing region at the oceanic front

Research Project

Project/Area Number 10640419
Research Category

Grant-in-Aid for Scientific Research (C)

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

Principal Investigator

YOSHIDA Jiro  Tokyo University of Fisheries, Department of Ocean Sciences, Associate Professor, 水産学部, 助教授 (30174931)

Co-Investigator(Kenkyū-buntansha) NAGASHIMA Hideki  Tokyo University of Fisheries, Department of Ocean Sciences, Professor, 水産学部, 教授 (10087570)
Project Period (FY) 1998 – 1999
Project Status Completed (Fiscal Year 1999)
Budget Amount *help
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1999: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1998: ¥2,000,000 (Direct Cost: ¥2,000,000)
KeywordsOyashio Front / Temperature inversion / Double diffusive convection / Neutral surface / cabbeling / Salt finger / thermobaric effect / Kelvin-Helmholtz instability / 常磐鹿島沖 / 水平貫入 / 異水魂 / 中立面解析 / 低塩分水 / thermobaric効果 / Lock-exchange型流れ
Research Abstract

1. Detailed CTD, XCTD and ADCP data at the Oyashio Frontal region were analyzed.
(1)Temperature inversion layers were frequently observed as the Oyashio Water mass extended from north. Hot/salty and cold/fresh water masses were piled up alternatively in the vertical direction suggesting the active double diffusive convection.
(2)Temperature inversion layers were observed more at the offshore region than the coastal region. And the strong temperature inversions were observed more at the northern area where the Oyashio and the Kuroshio waters were contacted directly.
(3) Neutral surface analysis was applied for the Oyashio region to the Kuroshio Extension, which reveals the important role of cabbeling and salt finger convection to the modification process of the Northa Pacific Intermediate Water (NPIW).
2. To understand the deep convection process at the polar region, thermobaric effect on the onset of deep convection was conducted.
(1) With the introduction of thermobaric effect, deep convective plumes were occurred even when the fluid layer was stably stratified.
(2) As for the case when the double diffusive effect is introduced to the above case, the onset of convection was suppressed by the double diffusion.
3. Double diffusive lock exchange flow is investigated numerically, and as a result, Kelvin-Helmholtz instability usually appeared at the interface was suppressed by the introduction of double diffusive convection.

Report

(3 results)
  • 1999 Annual Research Report   Final Research Report Summary
  • 1998 Annual Research Report
  • Research Products

    (7 results)

All Other

All Publications (7 results)

  • [Publications] M. Nagasaka: "On the double diffusive intrusion observed in the Oyashio frontal region"Theoretical and Applied Mechanics. 48. 393-408 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] J. Yoshida: "Numerical experiments on double diffusive gravity curve***"Theoretical and Applied Mechanics. 48. 385-392 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] M. Nagasaka, J. Yoshida, H. Nagashima, M. Matsuyama, K. Kawasaki and K. Yokouchi: "On the double diffusive intrusion observed in the Oyashio frontal region"Theoretical and Applied Mechanics. 48. 393-408 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] J. Yoshida and H. Nagashima: "Numerical experiments on double diffusive gravity currents"Theoretical and Applied Mechanics. 48. 385-392 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] M.Nagasaka: "On the double diffusive intrusion observed in the Oyashio frontal region"Theoretical and Applied Mechanics. 48. 393-408 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] J.Yoshida: "Numerical experiments on double diffusive gravity currents"Theoretical and Applied Mechanics. 48. 385-392 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] R.Inoue: "Vertical mixing processes to change density of North Pacific Intermediate Water around mixed water religion"J.P.O.投稿予定. (2000)

    • Related Report
      1999 Annual Research Report

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Published: 1998-04-01   Modified: 2016-04-21  

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