The Global Importance of Increasing Design Rainstorms under Specific Return Periods in China

Evaluating the correlation between changes in design rainstorms and extreme rainstorm events under climate change facilitates flood control and disaster reduction. Based on the daily rainfall data of 609 stations during 1958-2017, the Pearson-III curve, least square method, F-test, and other methods were adopted to study the changes in design rainstorms and the response to extreme rainstorms over nearly 60 years in China, and to explore the flood control capacity of engineering during climate change. The conclusions are as follows. (1) There is a general increasing trend in extreme rainstorm events in China. Most extreme rainstorm indices present upward trends in East China (EC), South China (SC), Central China (CC), Northwest China (NW), and Southwest China (SW) and downward trends in Northeast China (NE) and North China (NC). (2) The temporal series of design rainstorms shows general growth under each return period in China. In EC, SC, and SW, the design rainstorms increase significantly with rates of 3.0, 3.1, and 1.3 mm/10a, respectively, in the 20-year return period, while they decrease significantly by -2.0 mm/10a in NC (p < 0.05). (3) Design rainstorms have a positive response to extreme rainstorm events, which resulted in increasing rainstorms in a specific return period in EC, SC, NW, and SW. These results can promote the revision of engineering design standards and improve the flood control capability of engineering.