Spatial risk occurrence of extreme precipitation in China under historical and future scenarios

In recent years, extreme precipitation events have shown a significant increasing trend in both intensity and amount. Therefore, it is urgent to delineate the areas vulnerable to extreme precipitation and formulate more reasonable measures to reduce the risk of extreme precipitation. In this study, we selected gross domestic product, population, nighttime light, normalized difference vegetation index, runoff depth, and relief degree of land surface data to comprehensively characterize surface vulnerability. We selected the 90, 95, and 99% precipitation quantiles and their occurrence frequencies in the historical and future periods as hazard factors, and calculated the extreme precipitation risks faced by different regions of China based on a risk calculation formula. The results indicate that the Qinghai-Tibet Plateau and urbanized regions such as the Yangtze River Delta are high-risk areas affected by extreme precipitation. The precipitation simulated by the Beijing Climate Center climate system model version 2 (BCC-CSM2-MR) global climate model selected in this study is relatively smaller than the historical precipitation, but it can basically reflect the actual spatial distribution characteristics of precipitation. Under four future climate scenarios, the joint occurrence probability of extreme precipitation will decrease, while high-risk areas of extreme precipitation will still be located in the Qinghai-Tibet Plateau and densely urbanized areas. This study systematically analyzed the spatial distribution characteristics of extreme precipitation risk under historical and future scenarios, providing theoretical support for the formulation of more reasonable measures to prevent extreme precipitation risk.