Non-stationary frequency analysis of extreme rainfall using meteorological variables: focusing on Yangpyeong region in Korea

The extreme rainfall is gradually increasing due to the effects of climate change, and as the climate begins to change more and more clearly, the frequency and intensity of damage caused by extreme rainfall events such as typhoons and heavy rainfall are increasing. The basic assumption of the classical hydrologic frequency analysis is that the climate and hydrologic events are stationary. However, as the characteristics of extreme rainfall are changing due to climate change, the application of non-stationary frequency analysis of extreme rainfall is getting more important. Climate Change Model output data is generally used to reflect future climate change. While the current climate models have reliably simulated the patterns of temperature change in large areas, it has been reported that there are still many problems from the viewpoint of stably simulating extreme rainfall events in a small area. Therefore, looking at the response of extreme rainfall from global warming to temperature data will be one of the reasonable approaches. In this presentation, a non-stationary frequency analysis of extreme rainfall is performed for Yangpyeong meteorological station in Korea, considering various meteorological variables such as surface air temperature (SAT) and dew-point temperature (DPT). The rainfall data from 1973 to 2017 are used, and the extreme sample data for the analysis is extracted by applying the Peaks over Threshold (POT) method. The Generalized Pareto Distribution (GPD) is applied to extracted data. The meteorological variable is reflected as a co-variate in estimating the scale parameter of GPD. Using the constructed non-stationary POT - GPD frequency analysis model using a meteorological co-variate, future design rainfall depth will be estimated that reflects changes in SAT or DPT under various future climate change scenarios.

Acknowledgement

This research was supported by a grant [MOIS-DP-2015-03] through the Disaster and Safety Management Institute funded by Ministry of the Interior and Safety of Korean government.