Estimation of Probable Maximum Precipitation and Probable Maximum Flood Through Maximization of Atmospheric Conditions

Abstract

 Flood damage from heavy rainfall is increasing recently, as Typhoon No. 12 in 2011 and the Kinu River flooding in 2015 demonstrate. Moreover, rainfall and flood discharge are expected to increase because of climate change. We specifically examined the Probable Maximum Precipitation (PMP) and Probable Maximum Flood (PMF) depending on rainfall durations and basin areas through atmospheric conditional change for upstream areas of the Yattajima, Tone River Basin. We proposed an index correlated with rainfall using the WRF model, and evaluated its maximum value using long-term data to estimate PMP and PMF.

 Results show the following: (1) Moisture fluxes show high correlation with 12-hr to 72-hr rainfall, for the upstream basin of Yattajima, and for its sub-basins through WRF model calculation in the area, which suggests that they can be used as suitable parameters to estimate PMP. (2) Estimation methods of PMP were shown by maximum moisture flux for the past 100 years and by climate model outputs for RCP8.5 scenario. (3) Temporal and areal distributions of PMP depend on the type of typhoon and/or front. (4) PMFs were evaluated using a run-off model for heavy rainfall patterns in current and climate change conditions.