The effect of climate change on Korean drought occurrences using a stochastic soil water balance model

摘要

In this study, the effect of climate change on drought occurrence is modeled using a conceptual soil water model and results from the model are analyzed. Future climatic data are prepared by applying climate information drawn by four global climate models in accordance with greenhouse gas emission scenarios A2, A1B and B2 to the spatio-temporal changing factor method which is a relatively simple statistical downscaling method to downscale the climate information to 60 meteorological observation points in Korea. Using a conceptual soil water model that can simulate temporal evolution of the soil water probability density function, changes in the soil water probability density function relative to climate changes are analyzed. Based on these changes in the probability density function, we can see that drought will occur more frequently in Korea in future. Since drought is not an absolute quantitative concept but is a spatiotemporally relative concept and is not an average event in terms of probability, it will be more realistic to define it as an extreme event with a low probability to occur at a site during a period and from this viewpoint, the quantile comparison method (that is, comparing the non-exceedance probability of drought occurrence of now with that of the future based on the reference soil water) applied in this study is expected to be appropriately applicable to the evaluation of the effects of extreme hydrologic events.