1960—2019年永定河流域降水演化特征.

Based on the daily rainfall data and interpolation data of 53 meteorological stations in and around the Yongding River Basin in the past 60 years, the evolution characteristics of precipitation in the Yongding River Basin from 1960 to 2019 were analyzed by various variation diagnosis methods. The results show that a) the annual rainfall in the Yongding River Basin has a downward trend. On the seasonal scale, the summer rainfall has a significant downward trend, and the spring, autumn and winter rainfalls have an upward trend. b) In terms of spatial distribution, the annual precipitation shows an insignificant downward trend in most areas, a significant downward trend in a small area below the Guanting Reservoir, and an insignificant upward trend in spring, autumn and winter, only an insignificant downward trend in some areas. On the contrary, the summer precipitation shows a downward trend in most areas of the basin. c) After the abrupt change of precipitation, the distribution function of annual precipitation increases at the minimum value and decreases at the maximum value, and the distribution function of precipitation in July and August decreases as a whole. [ABSTRACT FROM AUTHOR]