Flood forecasting on the mountainous river basin by using the most advanced Multi-parameter radars

游击暴雨（Guerrilla Heavy Rainfall， GHR）是一种局部强降雨，在日本引发了山洪灾害。预测局地强降雨风险，特别是GHR风险，对于预防水文气象灾害和尽量减少人类生命财产损失至关重要。气象和水文方面的研究已经开展，以制定准确预测和警报山洪暴发的方法。在气象方面，提出了基于物理机制对GHR引发的风险进行定量预测的方法。通过多普勒雷达分析，对变量进行了估计。然后，通过多元线性回归建立了预测风险水平与各变量之间的相关性。在水文方面，山洪引导（FFG）被认为是确定是否发生山洪暴发的标准。FFG是在特定时期内引发流域洪水所需的降水量。基于阈值径流（TR）和土壤水分亏缺（SD），利用暴雨水管理模型（SWMM）估算了FFG。利用地形和气象资料，估算了城乡混合土地利用的FFG。因此，一旦FFG建立，FFG就可以在山洪多发地区发布山洪预警，而无需运行整个水文气象过程。为了防止山洪暴发，山洪警报应该同时考虑定量风险预测（气象学）和山洪暴发预警（水文学）。

Guerrilla Heavy Rainfall (GHR), a type of localized heavy rainfall, has caused flash flood disasters in Japan. Predicting the risk of localized heavy rainfall, especially GHR, is crucial for preventing hydro-meteorological disasters and minimizing damage to human life and property. Research in meteorology and hydrology has been conducted to develop methods for accurately predicting and alerting flash floods. Meteorologically, the quantitative risk prediction method was developed for predicting the risk triggered by GHR based on the physical mechanism. By multiple Doppler radar analysis, the variables were estimated. Then, the correlation between the predicted risk level and the variables was founded on the multilinear regression. Hydrologically, flash flood guidance (FFG) was considered to determine the criteria for whether flash floods occur. FFG is the amount of precipitation needed in a specific period to initiate flooding in the watershed. FFG was estimated based on Threshold Runoff (TR) and Soil moisture Deficit (SD) using the Storm Water Management Model (SWMM). By using topographic and meteorological data, the FFG was estimated on the mixed land use consisting of the rural and urban areas. So, once the FFG has been established, the FFG can issue flash flood warnings without running the entire hydro-meteorological process in the region where flash floods frequently occur. To prevent flash floods, flash flood alerts should be taking into account both the quantitative risk prediction (meteorology) and flash flood warnings (hydrology).