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The estimation of nutrient salt flux from the outer ocean into the coastal region based on the multi-scale ocean model

Research Project

Project/Area Number 13650563
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 水工水理学
Research InstitutionTokyo Institute of Technology

Principal Investigator

YAGI Hiroshi  Tokyo Institute of Technology, Graduate school of Science and Engineering, Associate Professor, 大学院・理工学研究科, 助教授 (80201820)

Co-Investigator(Kenkyū-buntansha) HINATA Hirobumi  National Institute for Land and Infrastructure Management, Senior researcher, 国土技術政策総合研究所, 主任研究官 (70272680)
KANDA Manabu  Tokyo Institute of Technology, Graduate school of Science and Engineering. Associate Professor, 大学院・理工学研究科, 助教授 (90234161)
Project Period (FY) 2001 – 2002
Project Status Completed (Fiscal Year 2002)
Budget Amount *help
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2002: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2001: ¥2,900,000 (Direct Cost: ¥2,900,000)
KeywordsNutrient salt / Kuroshio fluctuations / Coastal upwelling / Open coast / semi-enclosed bay / Middle layer intrusion / Field observation / Numerical experiment / 外洋水進入 / 東京湾 / 密度流 / 数値モデル / 季節変動 / 底層流入 / 黒潮 / 親潮 / 現地計測 / クロロフィルa / 基礎生産力
Research Abstract

In order to estimate and understand the mechanism of nutrients flux from the outer ocean to the coastal region, two different types of coastal area were investigated. In the first case, field observations were carried out within the Kashima coastal region to understand the effect of the Kuroshio Current on the nutrient salt distribution and primary production along the Kashima open coast. The observations showed there is a surge in the concentration of nutrient salts, the duration of the surge, at one or two months. Comparison with observations made in previous periods showed that there are two kinds of response of the Kashima coastal current system to the approaching Kuroshio. When the approaching Kuroshio is not close to the coastal region, an anticlockwise gyre is induced off the Kashima coast and low-salinity and low-temperature water intrudes from the northern area (Jyoban coast) to the coastal region. When the approaching Kuroshio is close to the coastal region, high-nutrient water wells up from the offshore bottom layer. In the second case, numerical experiment were performed for Tokyo bay to understand the intrusion process of oceanic water into a semi-enclosed estuary. The simulation results showed that the oceanic water induction process involves transition between two kinds of flow structure : the normal estuary circulation type (two layers) and middle layer intrusion type (three layers). While the three layer structure is apparent, oceanic water intrudes into the middle layer of eastern part of Tokyo bay and coastal water at surface and bottom layer outflows through the western Dart of Tokyo bay. This agrees well with field observation. An annual analysis based on the numerical experiment results showed that the intensity and structure of oceanic water intrusion exhibits remarkable seasonal variation, hence intrusion in summer is stronger and the core of oceanic intrusion water is closer to the surface than that in winter.

Report

(3 results)
  • 2002 Annual Research Report   Final Research Report Summary
  • 2001 Annual Research Report
  • Research Products

    (20 results)

All Other

All Publications (20 results)

  • [Publications] 八木 宏, 片岡理英子, 藤原建紀: "東京湾における外洋水進入特性に関する数値実験"土木学会海岸工学論文集. 50(印刷中). (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] 八木 宏, 栃木謙, ブリラシド: "日本沿岸の内部潮汐波強度の推定"土木学会海岸工学論文集. 50(印刷中). (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] 八木 宏, 大森義暢, 高橋亜依: "多摩川河口域における流れと懸濁物質輸送特性について"土木学会海岸工学論文集. 50(印刷中). (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] 栃木謙, 八木 宏, ブリラシド, 小林智尚: "冬季日本海沿岸域に発達する傾斜流特性"日本流体力学会年会2002講演論文集. 488-489 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] 八木 宏, 大森義暢, 足立久美子, 二平 章, 高橋正和: "那珂川河口海域における物質分布構造の季節変化"土木学会海岸工学論文集. 49. 1026-1030 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] 八木 宏, 足立久美子, 二平 章, 高橋正和: "黒潮流路変動に伴う沿岸域への栄養塩流入現象"土木学会海岸工学論文集. 49. 1216-1220 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] 八木 宏, 身崎成紀, 灘岡和夫, 中山哲厳, 足立久美子, 二平章: "黒潮流路変動と前線渦が鹿島灘の広域沿岸水挙動に与える影響について"土木学会論文集. 719. 81-91 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] 八木宏, 灘岡和夫, 中山哲厳, 二平章: "鹿島灘沿海域における黒潮流路接近時の流動特性"海と空. 78. 45-50 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Hiroshi YAGI, Rieko KATAOKA, Hajime YAMAGUCHI and Tateki FUJIWARA: "Numerical experiments of oceanic water intorusion process in TOKYO BAY"Proceeding : of Coastal Engineering, JSCE. 50 (in printing). (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Ken TOCHIGI, Hiroshi YAGI and Bri Rachid: "Numerical simulation of internal tide intensity along the Japanese coast"Proceeding of Coastal Engineering, JSCE. 50 (in printing). (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Hiroshi YAGI, Yoshinobu OOMORI and Ai TAKAHASHI: "Field measurements of velocity field and sediment movement at the Tama river estuary"Proceeding of Coastal Engineering, JSCE. 50 (in printing). (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Ken Tochigi, Hiroshi YAGI, Bri Rachid and Tomonao KOBAYASHI: "The Numerical simulation of Slope currents developed along Japan Sea coast"Proceedings, 2002 Meeting of Japan Society of Fluid Mechanics. 488-489 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Hiroshi YAGI, Yoshinobu OOMORI, Kumiko ADACHI, Akira Nihira and Masakazu TAKAHASHI: "Spatial and seasonal variation of salinity, nutrient salts and chlorophyll. A at the Naka river estuary"Proceeding of Coastal Engineering, JSCE. 49. 1026-1030 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Hiroshi YAGI, Kumiko ADACHI, Akira NIHIRA and Masakazu TAKAHASHI: "High nutrient water intrusion into the Kashima coast induced by Kuroshio axis fluctuations"Proceeding of Coastal Engineering, JSCE. 49. 1216-1220 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Hiroshi YAGI, Shigeki MISAKI, Kazuo NADAOKA, Akiyoshi NAKAYAMA, Kumiko ADACHI and Akira Nihira: "Effects of Kuroshio pass deflection and frontal eddies on meso-scale current dynamics at Kashima coast"Journal of Hydraulics, Coastal and Environmental Engineering, JSCE. 81-91 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Hiroshi YAGI, Kazuo NADAOKA, Akiyoshi NAKAYAMA and Akira Nihira: "Coastal current system of Kashima coast induced by an approaching of Kuroshio axis"Lar mer. 78. 45-50 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] 八木 宏, 片岡理英子, 藤原建紀: "東京湾における外洋水進入特性に関する数値実験"土木学会海岸工学論文集. 50(発表予定). (2003)

    • Related Report
      2002 Annual Research Report
  • [Publications] 八木 宏, 栃木謙, ブリラシド: "日本沿岸の内部潮汐波強度の推定"土木学会海岸工学論文集. 50(発表予定). (2003)

    • Related Report
      2002 Annual Research Report
  • [Publications] 八木 宏, 永澤 宏, 足立久美子, 二平 章: "鹿島灘沿岸域における栄養塩とクロロフィルaの時空間変動特性"土木学会海岸工学論文集. 49(発表予定). (2002)

    • Related Report
      2001 Annual Research Report
  • [Publications] 八木 宏, 永澤 宏, 足立久美子, 二平 章: "那珂川河口域における物質循環構造"土木学会海岸工学論文集. 49(発表予定). (2002)

    • Related Report
      2001 Annual Research Report

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Published: 2001-04-01   Modified: 2016-04-21  

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