Study on a real-time flood forecasting method for locally heavy rainfall with high-resolution X-band polarimetric radar information

摘要

In recent times locally heavy rainfall has occurred frequently in Japan and caused serious human accidents; hence the need for flood forecasting systems has increased to reduce inundation damage. However, flood forecasting that secures lead-time for evacuations is extremely difficult because conventional radars cannot adequately measure the rainfall. Under this circumstance, X-band polarimetric radars have been installed, and flood forecasting with a higher accuracy is expected. In order to develop and optimize a real-time flood forecasting method for locally heavy rainfalls in urban drainage areas, we have considered several flood forecasting models with various computational accuracies and loads. Furthermore, we have evaluated these models for comprehensive prediction accuracies through case studies in an actual basin using X-band radar information. As a result, the detailed flood forecasting model might not always have the highest accuracy and the proposed simplified model which can apply the latest rainfall information with lower computational loads was effective.