Projecting Multiscale River Flood Changes Across Japan at +2°C and +4°C Climates DOI Creative Commons
Jiachao Chen, Takahiro Sayama, Masafumi YAMADA

et al.

Earth s Future, Journal Year: 2025, Volume and Issue: 13(5)

Published: May 1, 2025

Abstract This study addresses computational challenges in high‐resolution, large‐domain, process‐based flood quantile estimation, focusing on Japan's future risks at 150 m resolution. Using the Aggregating Grid Event (AGE) method, Rainfall‐Runoff‐Inundation (RRI) model, and Peaks‐Over‐Threshold (POT) approach, it incorporates 2,160‐year precipitation data from a 5‐km dynamically downscaled ensemble (d4PDF DDSJP) across three climate stages (historical, +2°C, +4°C). The AGE method identified critical events for estimations POT was employed to estimate 100‐year discharge (Q100) over 2.2 million river grid cells. Key findings include: (a) Nationwide, is projected increase 1.16 times (+2°C) 1.37 (+4°C), with equivalent return periods reduced 45 years 23 (+4°C). Northern regions (Hokkaido Tohoku) are particularly climate‐sensitive, exceeding national averages Q100 increases. (b) Small basins transition zones plains mountains exhibit higher ratios, necessitating targeted prevention measures. (c) Flash expected rise, most seeing flashiness increases of 10% 20% Southern Japan faces further flash intensification, while under +4°C stage anticipates emerging related floods. underscores urgency adaptive management strategies mitigate increasing risks, offering foundation informed policymaking public‐engaged mitigation. Simulation opens pathways research cascading disaster scenarios +2°C climates.

Language: Английский

Projecting Multiscale River Flood Changes Across Japan at +2°C and +4°C Climates DOI Creative Commons
Jiachao Chen, Takahiro Sayama, Masafumi YAMADA

et al.

Earth s Future, Journal Year: 2025, Volume and Issue: 13(5)

Published: May 1, 2025

Abstract This study addresses computational challenges in high‐resolution, large‐domain, process‐based flood quantile estimation, focusing on Japan's future risks at 150 m resolution. Using the Aggregating Grid Event (AGE) method, Rainfall‐Runoff‐Inundation (RRI) model, and Peaks‐Over‐Threshold (POT) approach, it incorporates 2,160‐year precipitation data from a 5‐km dynamically downscaled ensemble (d4PDF DDSJP) across three climate stages (historical, +2°C, +4°C). The AGE method identified critical events for estimations POT was employed to estimate 100‐year discharge (Q100) over 2.2 million river grid cells. Key findings include: (a) Nationwide, is projected increase 1.16 times (+2°C) 1.37 (+4°C), with equivalent return periods reduced 45 years 23 (+4°C). Northern regions (Hokkaido Tohoku) are particularly climate‐sensitive, exceeding national averages Q100 increases. (b) Small basins transition zones plains mountains exhibit higher ratios, necessitating targeted prevention measures. (c) Flash expected rise, most seeing flashiness increases of 10% 20% Southern Japan faces further flash intensification, while under +4°C stage anticipates emerging related floods. underscores urgency adaptive management strategies mitigate increasing risks, offering foundation informed policymaking public‐engaged mitigation. Simulation opens pathways research cascading disaster scenarios +2°C climates.

Language: Английский

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