Proposal of New Indexes for Development Characteristics of Storm Surge Considering Topographical Features and Tides

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K14839
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 22040:Hydroengineering-related
• Research Institution: Kyushu University
• Principal Investigator: Ide Yoshihiko 九州大学, 工学研究院, 助教 (60866680)
• Project Period (FY): 2020-04-01 – 2022-03-31
• Keywords: 高潮 / 水防災 / 指標の提案 / 高潮増幅メカニズム

Outline of Final Research Achievements

This study was undertaken to develop the existing theory to better understand the mechanism of storm surge generation. As a result, I was able to derive a theoretical formula that is more accurate than the one that has been used in the past. In addition, I developed new theoretical formulas for the effect of the bathymetry of each bay on storm surge and for the effect of changes in water depth on storm surge. These indices can be used to understand the characteristics of each bay with respect to storm surge. The application of these indices to major bays in Japan revealed that the seafloor topography of the Ariake Sea and Tokyo Bay contributes significantly to the amplification of storm surge, and that storm surge in the Ariake Sea is strongly influenced by tidal bathymetry and sea level rise due to global warming.

Free Research Field

海岸工学

Academic Significance and Societal Importance of the Research Achievements

本研究は地球温暖化の影響を受けて災害リスクが増大すると言われている高潮災害に対する防災対策を考える上で重要な成果を得た．これまでの高潮に対する理解をさらに深め，高潮を考える際に注目すべき事項についての知見を更新したことや，ここで導出した指標を各湾に適用することでその湾が持つ高潮に対する特徴を簡易的に瞬時に把握することができるようになった．この指標を用いることで地球温暖化に伴う海面上昇によって各湾で高潮がどのように変化するかを予想でき，また指標の値は各湾の今後の高潮防災対策をどのように優先順位を付けて実施していけばよいかを決定する有益な情報となる．