2023 Fiscal Year Research-status Report
Unravelling the Compound Effect from Storm Surge and Mean Sea Level Change in Asian Megacities
| Project/Area Number |
23K13531
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| Research Institution | The University of Tokyo |
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Principal Investigator |
イスラム エムディ・レズワノール 東京大学, 大学院工学系研究科(工学部), 特任研究員 (80973768)
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| Project Period (FY) |
2023-04-01 – 2026-03-31
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| Keywords | storm surge / mean sea level rise / compound flooding / tropical cyclone / ensemble forecasting |
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| Outline of Annual Research Achievements |
We have completed investigating spatiotemporal changes in storm surge levels in Japan from 1980 to 2019, a period when observational platforms including tide gauges and storm records are highly consistent. We find statistical evidence supporting the increase in surge annual maxima in several places including the bay area of Tokyo since 1980. This rate of change is comparable to that observed for mean sea level (MSL) rise over the same period. These findings cast doubt on the current hypothesis underlying the flood adaptation plan, which assumes that future surge extremes will remain the same and only considers MSL changes. We demonstrate that the changes in extreme sea level (ESL) in the last 40 years cannot be explained by the rise of MSL alone. Rather, the northeastward shifting of tropical cyclone (TC) landfall location along with intensifying and widening of TCs, might have altered the likelihood of ESL, including surge extremes. The substantial influence of these TC meteorological variables on surge levels combined with the rise of MSL, suggests that current coastal planning practices including critical heights for flood defenses might be inadequate in the future.
We have also conducted ensemble forecasting of TC Hagibis including storm surge disasters in central Japan where worst case scenarios were reproduced reasonably well and suggest Papreto optimality is a novel way to select ensemble member that characterize worst case.
All these results are already published in international peer reviewed journals and presented several academic societal conferences.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
We have been able to compile and process the statistical data for Japan before the deadline we set. The relevant results are well documented, published, and presented in planned conferences which all happened within the reasonable timeframe.
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| Strategy for Future Research Activity |
We are now proceeding to compile and analyze the statistical data for other Asian mega cities. We plan to conduct several field surveys in this fiscal year and disclose the results as soon as possible.
At this stage, we are struggling to hire potential part time researchers to assist project works. This is very crucial to carry out the project works smoothly and we are optimistic that we will get potential researchers soon.
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| Causes of Carryover |
In the first year of grant, although we planned for conducting two field surveys in Vietnam and Bangladesh, respectively, we decided to do it in the 2nd year of the grant. It is due to some unavoidable issues including visa acceptance. Therefore, we plan to use residual first year grant amount along with 2nd year grant amount.
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