[A-HW20] 水循環・水環境

[AHW20-05] A review of ensemble flood forecasting for operational warning

*渡辺 恵¹、伊藤 舜将²、馬 文超¹、山﨑 大¹ (1.東京大学 生産技術研究所、2.東京大学大学院 工学系研究科)

キーワード：アンサンブル、洪水、予測、確率的、コミュニケーション

There is growing international interest in the potential of ensemble flood forecast to improve operational warning. Ensemble flood forecasting systems promise two significant advantages over conventional deterministic forecasting techniques depending on water level observations of upstream rivers. First, ensemble flood forecasting systems have a long lead time for effective evacuation. Second, ensemble flood forecasting systems can also provide quantitative probability to estimate the uncertain forecasts. The introduction of an ensemble flood forecasting system has been under consideration in Japan. We need a comprehensive and integrated assessment based on multiple information from ensemble flood forecasting systems. This study surveyed ways to deliver detailed information in operational ensemble flood forecast systems outside of Japan. We summarized effective visualizations and improvements of the forecast systems by user feedbacks. We found that forecasts with multiple variables are delivered to public administration units with low spatial resolution while forecasts with fewer variables are delivered to each local point or each river segment with high spatial resolution. We also found that user feedbacks have improved the forecasts systems through discussions, although ensemble forecasts are complicated, and they have different characters from local forecasts. Communication with potential users concerning the forecasts is necessary for an effective operation.