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Changes in Antarctic Bottom Water and its curculation caused by "regime shift" changes originated from Mertz Glacier Tongue collapse

Research Project

Project/Area Number 19K03981
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 17020:Atmospheric and hydrospheric sciences-related
Research InstitutionJapan Agency for Marine-Earth Science and Technology

Principal Investigator

Kobayashi Taiyo  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), 主任研究員 (10360752)

Project Period (FY) 2019-04-01 – 2024-03-31
Project Status Completed (Fiscal Year 2023)
Budget Amount *help
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2021: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2020: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Keywords南極底層水 / 長期トレンド / レジームシフト / メルツ氷河舌崩壊 / 深海アルゴ / 深層循環
Outline of Research at the Start

本研究では、豪州南極海盆110°E付近の歴史的観測データおよび最近の船舶・深海用フロート観測データを用いて、同海域における南極底層水の長期的変化および2010年以降に生じたその変調について詳細な解析を行うことにより、2010年のメルツ氷河舌崩壊に起因した南極底層水の「レジームシフト」的変化の空間的な広がりを明らかにするとともに、アデリー海岸沖で観測された変化との差異から、豪州南極海盆における南極底層水の循環や変質過程を定量的に明らかにする。

Outline of Final Research Achievements

This study developed a long-term time-series of temperature, salinity, and layer thickness for Antarctic Bottom Water (AABW) off the Wilkes Land coast in the Australian-Antarctic Basin. The main results are the following. (1) AABW there has the warming, freshening, and contracting trends; these had begun in the 1970's, at latest. (2) The long-term trends of AABW seem to be reversed in the middle of the 2010's. (3) Salinization of the deepest AABW, which has been observed since the middle of 2010's in the eastern Australian-Antarctic Basin widely, was fundamentally caused by a slow-down of AABW freshening, which is likely to be caused by the Mertz Glacier Tongue collapse.

Academic Significance and Societal Importance of the Research Achievements

南大洋に起源を持つ南極底層水が高温・低塩化し、その体積が減少していることは広く観測されている。しかし、その知見のほとんどは、1990年以降、10年程度の間隔を空けて数回実施された船舶観測結果に基づくものであり、1990年以前の状況や、その変化の詳細についてはほとんど不明であった。本研究は歴史的観測データから長期の時系列データを作成することで、海域は限られるものの1930年代からの南極底層水の変化を示すことに成功した。また、豪州南極海盆東部域の広範囲で近年報告されている南極底層水の「高塩化」が生じるメカニズムを明らかにし、その真の原因は南極底層水の低塩化の停滞にあることを示した。

Report

(6 results)
  • 2023 Annual Research Report   Final Research Report ( PDF )
  • 2022 Research-status Report
  • 2021 Research-status Report
  • 2020 Research-status Report
  • 2019 Research-status Report
  • Research Products

    (11 results)

All 2023 2021 2020 2019 Other

All Int'l Joint Research (2 results) Journal Article (2 results) (of which Int'l Joint Research: 1 results,  Peer Reviewed: 2 results,  Open Access: 1 results) Presentation (7 results) (of which Int'l Joint Research: 4 results)

  • [Int'l Joint Research] University of Tasmania/CSIRO Oceans and Atmosphere(オーストラリア)

    • Related Report
      2021 Research-status Report
  • [Int'l Joint Research] Scripps Institution of Oceanography(米国)

    • Related Report
      2021 Research-status Report
  • [Journal Article] Changes in Antarctic bottom water off the Wilkes Land coast in the Australian-Antarctic Basin2023

    • Author(s)
      Kobayashi Taiyo
    • Journal Title

      Deep Sea Research Part I: Oceanographic Research Papers

      Volume: 195 Pages: 104040-104040

    • DOI

      10.1016/j.dsr.2023.104040

    • Related Report
      2023 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Deep Argo reveals bottom water properties and pathways in the Australian-Antarctic Basin2021

    • Author(s)
      Foppert, A., Rintoul, S. R., Purkey, S. G., Zilberman, N., Kobayashi, T., Sallee, J.-B., van Wijk, E. M., Wallace, L. O.
    • Journal Title

      Journal of Geophysical Research: Oceans

      Volume: 126 Issue: 12

    • DOI

      10.1029/2021jc017935

    • Related Report
      2021 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Presentation] 南極オーストラリア海盆ウィルクスランド沖における南極底層水の変化2023

    • Author(s)
      小林大洋
    • Organizer
      Japan Geoscience Union Meeting 2023
    • Related Report
      2023 Annual Research Report
  • [Presentation] Changes in Antarctic bottom water off the Wilkes Land coast in the Australian-Antarctic Basin2023

    • Author(s)
      Kobayashi, T.
    • Organizer
      IUGG 2023
    • Related Report
      2023 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Changes of Antarctic Bottom Water off the Wilkes Land coast of the Australia-Antarctic Basin2020

    • Author(s)
      Taiyo Kobayashi
    • Organizer
      JpGU-AGU Joint Meeting 2020: Virtual
    • Related Report
      2020 Research-status Report
    • Int'l Joint Research
  • [Presentation] オーストラリア-南極海盆ウィルクスランド沖における南極底層水の経年変化2020

    • Author(s)
      小林大洋・嶋田啓資・北出裕二郎・溝端浩平
    • Organizer
      日本海洋学会2020年度秋季大会(Virtual)
    • Related Report
      2020 Research-status Report
  • [Presentation] Changes of Antarctic Bottom Water in the central region (near 115°E) of the Australia-Antarctic Basin2020

    • Author(s)
      Taiyo Kobayashi
    • Organizer
      Ocean Sciences Meeting 2020
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research
  • [Presentation] オーストラリア-南極海盆中部域における南極底層水の経年変化2019

    • Author(s)
      小林大洋
    • Organizer
      日本海洋学会秋季大会
    • Related Report
      2019 Research-status Report
  • [Presentation] Changes of Antarctic Bottom Water in the central region (near 115°E) of the Australia-Antarctic Basin2019

    • Author(s)
      Taiyo Kobayashi
    • Organizer
      第10回極域科学シンポジウム
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research

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Published: 2019-04-18   Modified: 2025-01-30  

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