关键词: 极端降水, 影响因素, 季风边缘区, 石羊河流域

Abstract: Global warming leads to an overall increase in atmospheric humidity and precipitation intensity, which aggravates the occurrence of extreme precipitation events. Scientific understanding of regional variations of extreme precipitation and its impacts is of great practical significance to the management and rational utilization of water resources, ecological protection and governance, and sustainable development of agriculture. Based on the daily precipitation data of four meteorological stations in the Shiyang River Basin from 1960 to 2018, we used unitary linear regression analysis and correlation analysis to analyze the variations and influencing factors of extreme precipitation in the Shiyang River Basin. The results showed that the values of extreme precipitation indices of the whole basin were on the rise except the consecutive dry days and wet days. Among them, the annual total precipitation, very wet days, and extremely wet days had a significant upward trend. Spatially, except consecutive wet days, the change tendency rate of other extreme precipitation indices showed an obvious altitude gradient effect, that is, the higher the altitude, the greater the growth rate. The correlation of extreme precipitation with minimum temperature was stronger than that with maximum temperature, indicating that extreme precipitation is more sensitive to minimum temperature than maximum temperature. Under the background of global warming, the changes of extreme precipitation in Shiyang River Basin were the results of the interaction of different atmospheric circulation systems, such as Arctic Polar Vortex, Western Pacific Subtropical High, East Asian Trough, and Tibet Plateau circulation. The rise of regional temperature exacerbated the occurrence of extreme precipitation events.

Key words: extreme precipitation, influencing factor, monsoon marginal region, Shiyang River Basin.