Assessing hydrological impacts from climate change with hourly precipitation using temporal downscaling over South Korea

English Abstract:

The assessment of hydro-climatological variables through climate scenarios from the outputs of Global Climate Model (GCM) is essential for adapting and mitigating the changes. However, GCM outputs are too coarse to apply a basin scale. Temporal downscaling is required to obtain the hourly precipitation for analyzing a small or medium basin since only few or several hours are taken to peak flows after it rains. In the current study, the spatiotemporal distribution of downscaled hourly precipitation for RCP4.5 and RCP8.5 scenarios over South Korea is presented as well as its implications over hydrological responses. The results indicate that the mean of hourly precipitation significantly increases over the southern part of South Korea especially for the morning time and its increase gets lower at the later time of a day in the RCP8.5 scenario. However, the increase cannot be propagated to the mainland due to the mountainous areas in the southern part of the country. Furthermore, the hydrological responses employing a distributed rainfall-runoff model (Vflo^TM) show that there is significant increase in peak flow for RCP8.5 scenario while slight decrease for RCP4.5. The current study concludes that the employed temporal downscaling method is suitable for obtaining the hourly precipitation data from daily GCM scenarios. In addition, the rainfall runoff simulation through the downscaled hourly precipitation is useful for investigating the variations of the hydrological responses related with future scenarios.