[A-OS10] Continental Oceanic Mutual Interaction - Planetary Scale Material Circulationn

[AOS10-05] Hydrological Hindcasts and Parameterizations for Flash Floods Real-Time Forecasting of Typhoon Hagibis 2019 in Japan

*Josko Troselj¹, Han Soo Lee¹ (1.Graduate School of Advanced Science and Engineering, Hiroshima University)

Keywords:extreme river discharge, Typhoon Hagibis in Japan, CDRM hydrological model, SCE-UA optimization method, real-time flood forecasting

As a result of climate change, unprecedented heavy rainfall disasters are increasingly occurring worldwide. It is therefore important to develop Early Warning Systems for real-time forecasting of extreme river water levels and discharges. This study applies the Cell Distributed Runoff Model version 3.1.1 (CDRM) hydrological model with five river basin parameters calibrated by the Shuffled Complex Evolution optimization method developed at the University of Arizona (SCE-UA) for nine first-class river basins in north-eastern Japan, to obtain hydrological parameterizations and hindcasts of river mouth discharge hydrographs during the Typhoon Hagibis 2019. The CDRM accurately projected river mouth discharges from three Japanese typhoons (Hagibis-2019, Roke-2011 and Chataan-2002) using calibrated parameter sets from each typhoon. Using this approach, this study produced cross-validation results with very high reproducibility metrics. Therefore, this study’s results show that the methodology and model used in the study has the capability of simulating extreme discharge events by calibrations using previous extreme typhoon case events with similar trajectories. Then, the calibrated parameter sets from the three typhoons were applied with forecasted rainfall data from Typhoon Hagibis for all nine rivers to project and validate possibilities and accuracy of real-time forecasting of river mouth hydrographs. These findings contribute to developing the real-time forecasting tools for extreme river discharges during unprecedented heavy rainfall-induced flash floods.