Abstract:
In recent years, frequent occurrences of extreme precipitation in Sichuan Province have caused huge economic and personnel losses. A comprehensive understanding of the regular pattern of extreme precipitation is of vital importance for managing and reducing the losses caused by extreme precipitation. Based on the daily precipitation data from 145 meteorological stations in Sichuan Province from 2007 to 2020, six extreme precipitation indexes were used to analyze the temporal and spatial variations of extreme precipitation in Sichuan Province. The results are as follows: Spatially, the values of extreme precipitation indexes were the largest in northeastern Sichuan Province and the western part of the Sichuan Basin, and the variation trends presented obvious geographical differences. Extreme precipitation indexes showed a significant decrease trend in northeastern Sichuan Province and an opposite trend in the western part of the Sichuan Basin; most stations in the rest regions displayed an obvious increase trend; And only a few stations displayed a decrease trend. Temporally, all the extreme precipitation indexes in Sichuan demonstrated an increasing trend, which means extreme precipitation has an increasing trend in the province. In the three sub-regions of Sichuan Province—the central and western parts of the basin and the western high-altitude area—the variations of extreme precipitation were similar to those of the whole Province; In northeastern Sichuan, the other indexes of extreme precipitation decreased except PRCPTOT, and extreme precipitation significantly decreased. The contribution rate of extreme precipitation to the total precipitation in Sichuan Province showed an increase trend, and the precipitation became more extreme, especially from 2017 to 2020. The trend of the contribution rate in the central and western parts of the basin was similar to that of the whole province, while the contribution rate in northeastern Sichuan had an opposite trend. Besides, the trend of the contribution rate in the western high-altitude area increased slowly. Precipitation in Sichuan Province increased in spring, summer and autumn, meanwhile the total extreme precipitation obviously increased in summer. Moreover, the amount and intensity of extreme precipitation reached their peaks in August while showing a decrease trend in July. To sum up, the extreme precipitation in Sichuan Province is the heaviest in August.