講演情報
[IS-01]Duration- and Rarity-Dependent Scaling of Extreme Precipitation
with Warming: Insights from Stochastic Storm Transposition of Large Climate Ensembles
*Wasitha Randeepa Ranga Dilshan1, Yusuke Hiraga1, Daniel Wright2 (1. Department of Civil and Environmental Engineering, 2. Department of Civil and Environmental Engineering, University of Wisconsin-Madison)
キーワード：
Extreme Precipitation Scaling、Large-Ensemble Climate Simulation、Stochastic Storm Transposition
Extreme precipitation is intensifying with climate change, yet how scaling varies with storm duration and event rarity remains unclear, particularly for very low annual exceedance probabilities AEPs relevant to probable maximum precipitation. This study integrates Stochastic Storm Transposition SST with the 5 km d4PDF large ensemble dataset to assess scaling across durations 1 to 48 h and AEPs 10^-1 to 10^-5 over the Mogami watershed, Japan. Synthetic 100000 year records enable robust estimation of rare extremes. Ensemble mean scaling remains near or below Clausius Clapeyron rates about 4 to 7 percent per K, while maxima exceed them, reaching about 20 to 24 percent per K for short durations. The 24 hour duration shows sustained super CC scaling, whereas longer durations exhibit declining mean scaling at rare AEPs. Increasing ensemble spread toward rarer events highlights irreducible uncertainty, emphasizing the need to incorporate both duration and rarity in probabilistic PMP estimation.