Change Characteristics of Extreme Precipitations and Estimation of Precipitation in Different Return Periods in the Qingjiang Basin of the Yangtse River

Based on the observations from 10 rain gauges from 1960 to 2016 in the Qingjiang Basin, this study aimed to discuss the spatial and temporal distributions of extreme precipitations in the Qingjiang Basin area using extreme daily precipitation, extreme precipitation, and extreme precipitation duration as extreme parameters, and provide the extreme precipitation spatial distribution and variation analysis of different time scale return periods based on the generalized extremum theory. The findings revealed that the maximum daily precipitation in the Qingjiang Basin was low in the upstream, downstream, and north, and high in the south. The upstream had always been a small area with extreme daily precipitation. The maximum value was located in the south of the basin, and the position alternated with the change in the age. The maximum extreme process precipitation exhibited a decreasing distribution from west to east. The rainfall in the upstream precipitation process was significantly greater than that in the downstream, and the spatial distribution of the corresponding precipitation days showed larger values in the south and the upstream, and smaller values in the north and the middle and lower reaches. The average precipitation was greater in the 1980s than in the 1960s and 1970s. In the 21st century, the maximum extreme continuous precipitation intensity was significantly reduced. The extreme longest process precedence presented two distinct extreme centers, and the corresponding precipitation days were high in the upstream and low in the middle and lower reaches. The return period of the Qingjiang Basin extreme precipitation was significantly different. The spatial distribution of the extreme daily precipitation at different return period levels was larger in the north than in the south, and smaller in the upper and lower reaches than in the midstream.