Research on improving predictability of coastal disasters caused by illusive cyclones

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H02260
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 22040:Hydroengineering-related
• Research Institution: Osaka Metropolitan University (2022); Osaka City University (2020-2021)
• Principal Investigator: Nakajo Sota 大阪公立大学, 大学院工学研究科, 准教授 (20590871)
• Co-Investigator(Kenkyū-buntansha): 二宮 順一 金沢大学, 地球社会基盤学系, 准教授 (20748892) ; 金 洙列 熊本大学, くまもと水循環・減災研究教育センター, 准教授 (60508696)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 台風 / 微気圧波 / 気象津波 / 高潮 / 高波

Outline of Final Research Achievements

To understand the uncertainty of real-time typhoon forecasting, we analyzed the forecasts from the Japan Meteorological Agency (JMA) and identified specific characteristics of forecast errors in typhoon properties. We also developed a real-time typhoon probability model. Based on fixed-point observations around Osaka Bay, we established the relationship between the annual occurrence of micro-pressure waves and abnormal tidal levels. The meteorological model results revealed that micro-pressure waves are prominently caused by frontal passage and interactions with typhoons. To examine the impact of cyclone variations on the future climate field, we created a stochastic typhoon model considering a rise of 4°C/2°C. Additionally, we devised a simplified method to assess the risks of strong winds, storm surges, and high-velocity hazards using the output of the stochastic typhoon model. Lastly, we evaluated the future changes in bomb cyclones based on a 150-year forecast.

Free Research Field

海岸工学

Academic Significance and Societal Importance of the Research Achievements

台風災害予測の不確実性は減災行動の抑制因子であり，定量化し意思決定に取り込むことでレジリエントな社会創造へとつながる．気象津波の因子である微気圧波を，高精度微気圧計により年間を通じた多点モニタリングした事例は希少で，台風と前線の干渉による微気圧波群の発生などの日本周辺における気象津波の実態解明に貢献した．将来予測の不確実性評価における統計的モデリングの重要性はIPCC AR6でも強調されており，応用範囲の広い高潮・高波の簡易高速推定法を構築したことは影響評価研究を大きく進展させた．これにより大アンサンブル資料に基づく不確実性の幅を示すなどは他に類を見ない成果を提示した．