Estimation of Sub-daily Extreme Precipitation to Assess Climate Change Impact on Floods of Han River Basin in South Korea

Sub-daily extreme precipitation for a specified duration and return period is used in the estimation of floods for design purposes. Recent researches show that climate change has impact on the precipitation process at different temporal and spatial scales. The present paper is focused on climate change impact on floods of Han River basin in South Korea. Climate change simulation outputs from 5 GCMs under the A2 scenario were used to estimate daily extreme precipitations. Sub-daily extreme precipitations were estimated using the scale-invariance concept. In order to assess sub-daily extreme precipitations from climate change simulation outputs, precipitation time series were generated based on NSRPM (Neyman-Scott Rectangular Pulse Model) and modified using the ratio of precipitation over projection periods to historical one. Sub-daily extreme precipitations were then estimated from those series. Finally, peak flows were estimated for principal sites of Han River basin using HEC-1 model. It was found that floods in the future displayed increasing or decreasing trends for estimation methods of sub-daily extreme precipitation and different periods.