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In the context of global -warming, there are more frequent heavy rainstorms and extraordinary rainstorms, which leads to growingly severe rainstorm disasters. In previous studies, heavy rainstorms and extraordinary rainstorms were classified into rainstorms so that it was impossible to fully grasp the spatiotemporal pattern of heavy rainstorms and extraordinary rainstorms. Therefore, based on the daily precipitation data of 659 meteorological stations in China, this study calculated the rainfall amount, the rain day, and the rainfall intensity of rainstorms, heavy rainstorms, and extraordinary rainstorms in 1951-2010, and analyzed the spatiotemporal patterns of rainstorms, heavy rainstorms, and extraordinary rainstorms in China. The results showed that: In terms of the proportion to the total rainstorms, rainstorms were the largest, followed by heavy rainstorms and extraordinary rainstorms; in terms of time, the rainfall amount, the rain day, and the rainfall intensity of interdecadal rainstorms and heavy rainstorms in China show a dynamic increase trend; in terms of space, only the rainfall amount and rainy days had an expansion trend, while the rainfall intensity did not change much. Temporally, the rainfall amount and the rain day of interdecadal extraordinary rainstorms were characterized by "increase--decline--increase", while their rain intensity was characterized by "decline-increase-decline". Spatially, there was no significant change in the rainfall amount, the rain day, and the rainfall intensity of extraordinary rainstorms. In short, rainstorms in China were developing towards extremes, which might be a result of combination of human factors and natural factors. [ABSTRACT FROM AUTHOR]

In this study, based on the data on the frequency of waterlogging events and the number of waterlogging days of 1,638 stations from 1961 to 2016, a variety of mathematical statistics methods were used to analyze the spatiotemporal evolution of waterlogging events in eastern China. The results showed that: ① In terms of time, the annual frequency of waterlogging events and the number of waterlogging days in eastern China in 1961–2016 showed an increasing trend despite of fluctuations. In the interdecadal changes, the highest frequency of waterlogging events and the greatest number of waterlogging days occurred in the 1990s, and from the 1960s to the 1980s, the frequency of waterlogging events and the number of waterlogging days in eastern China showed a decreasing trend. There were 6-year and 30-year periodic variations in the frequency of waterlogging events and the number of waterlogging days in eastern China, and mutations occurred in 1991. ② In terms of space, from 1961 to 2016, the areas with high frequency of waterlogging events in various years in eastern China were mainly South China, western and southern Yunnan, northern Jiangsu, southern Zhejiang, northern Fujian, junction areas between Hunan and Chongqing, northern Sichuan, and eastern Liaoning. ③ In the spatial distribution of change trends and fluctuation characteristics, the frequency of waterlogging events and the number of waterlogging days in eastern China increased significantly in the southeastern coastal areas from 1961 to 2016, and the fluctuations of the frequency of waterlogging events and the number of waterlogging days in eastern China from 1961 to 2016 presented a spatial variation pattern of low in the southwest and high in the northwest. [ABSTRACT FROM AUTHOR]