Analysis of the Characteristics of Short-Term Extreme Precipitation in China in the Last 30 Years

Because of the limitations of observational data, only very few studies have investigated the characteristics and thresholds of short-term extreme precipitation below the daily scale in the past. Based on the hourly precipitation data during 1991–2021 from 2464 stations in China, which is newly developed by China Meteorological Administration, this paper analyzes the frequency characteristics of the 1-h and 3-h precipitation in China, uses the percentile method to count the 1-h and 3-h extreme precipitation thresholds, and explores the climatic characteristics of short-term extreme precipitations in China. The analysis results show that the hourly precipitation frequency is relatively high (up to 12%) at some stations in Sichuan, Guizhou, Hunan, Jiangxi, Fujian, and Zhejiang provinces and is generally low (less than 3%) at most stations in Northwest China. From 1991 to 2021, the frequency of 1-h and 3-h extreme precipitation shows a decreasing trend. Among the stations, 64.7% demonstrate linear trends for the 3-h extreme precipitation frequency, which is in phase with that of the 1-h extreme precipitation frequency. The spatial characteristics of extreme precipitation and the extreme precipitation threshold in China are obvious. The extreme precipitation threshold of the 1-h precipitation shows large spatial characteristics in Southeast China and small in Northwest China. Compared with other regions in China, Guangdong, Guangxi, and Hainan have larger thresholds. The historical average extreme value for the 1-h precipitation in Hainan, Guangdong, Guangxi, and Jiangsu provinces exceeds 80 mm h⁻¹, with Hainan province exhibiting the highest average extreme value, reaching 102.7 mm h⁻¹.