Climate Change Impacts on Meteorological and Hydrological Droughts and Their Hazard Propagations in China

Abstract

Drought is a natural disaster that is receiving significant attention all over the world. Many studies have shown that drought will continue to be an overwhelming threat throughout the 21st century in the context of climate change. Meteorological and hydrological droughts, defined, respectively, as an abnormally dry climate and a deficit in surface or subsurface water availability, can be the most important from the perspective of social activities on water resources. Therefore, the quantification of climate change impacts on the development of meteorological and hydrological droughts at the regional scale is essential to make adaptation strategies for water resources management in advance. Even though previous research in recent years has extensively studied the drought propagation from meteorological to hydrological events, their hazard transferability has been less investigated, especially for future climate change scenarios. This study first quantifies the climate change impacts on meteorological and hydrological drought characteristics over a large number of small- to medium-sized catchments in China for two future periods by using a set of global climate model simulations and hydrological models. The hazard propagation from meteorological to hydrological droughts is then specifically investigated by using a bivariate framework with the most likely scenario. The results show that both meteorological and hydrological droughts are highly sensitive to future climate change. Specifically, both meteorological and hydrological droughts are projected to decrease in northern and especially northeastern China for the future periods, while some increases are projected in southern China. In particular, the change of hydrological droughts is more obvious than that of meteorological droughts. Similar results in drought changes are also observed for drought hazards from the bivariate perspective. In addition, there are significant correlations of joint return levels between meteorological and hydrological droughts, indicating the tight connections between meteorological and hydrological drought hazards. This relationship almost stays constant under the future climate change. Overall, this study indicates that the hazard propagation should pay specific attention under the current and future climates, especially taking into account the fact that the hazards of hydrological drought can be larger than that of meteorological drought.