Predicting the Risk Level of Guerrilla Heavy Rainfall by Using the Quantitative Risk Prediction Method with Multiple Doppler Radar Analysis

Abstract

Japan has suffered from devastating flood disasters caused by localized heavy rainfall known as Guerrilla heavy rainfall recently. For reducing the damage, it is necessary to predict the risk of GHR precisely. So, we aim to propose an accurate quantitative risk prediction method. One of the importance was that the relationship between the predicted risk level and the variables was considered depending on each rain stage because the variables showed different characteristics according to the development of the convective cloud. The other one was that the variables were estimated with real wind field data by multiple Doppler radar analysis. Then, the multilinear regression was used for finding the correlation between the predicted risk level and the variables with accuracy. The accuracy of multilinear regression was estimated by a Receiver Operating Characteristic analysis. As the result, the most appropriate regression among the relevant variables was composed of reflectivity, vorticity, divergence, and updraft by multiple Doppler radar analysis. It is possible to predict the risk quantitatively with high accuracy of 90% at the early rain stage.