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

游击性强降雨(GHR)是一种局部性强降雨，已在日本造成山洪灾害。预测局地强降雨，特别是GHR的风险，对于预防水文气象灾害，最大限度地减少对人类生命财产的损害至关重要。已经开展了气象学和水文学方面的研究，以开发准确预测和预警山洪的方法。在气象学上，基于物理机制，提出了定量风险预测方法，用于预测GHR引发的风险。通过多个多普勒雷达分析，对变量进行估计。然后在多元线性回归的基础上建立预测风险水平与变量之间的相关关系。在水文学上，洪水导则(FFG)被认为是确定是否发生山洪的标准。FFG是在特定时期内引发流域洪水所需的降雨量。利用雨水管理模型(SWMM)，根据临界径流(TR)和土壤水分亏缺(SD)估算FFG。利用地形和气象资料，估算了城市和农村混合土地利用的总基准量。因此，一旦FFG建立，FFG就可以发布山洪警告，而不需要在经常发生山洪的地区运行整个水文气象过程。为防止山洪暴发，山洪警报应同时考虑定量风险预测(气象学)和山洪警报(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).