关键词: 降水变化, 灞河流域, Mann-Kendall检验法, R/S分析法, 小波分析

Abstract: The aim of the present research is to better understanding the characteristics of climate change in the Bahe river drainage basin. The annual and inter-annual precipitation changes, the abrupt change time, and the variation period of precipitation are analyzed based on observations in the past half century. Moving-average method, R/S analysis, Mann-Kendall test, and wavelet analysis are adopted for the research. Results reveal that 1) from 1958 to 2012, precipitation presented a decline trend with fluctuations, and will keep declining in the next several years; 2) precipitation is extremely uneven in a year, mainly focused from July to September, decreasing obviously in spring and autumn, and rising slightly in summer and winter; 3) Hurst index of precipitation in four seasons are all less than 0.5, and the precipitation series have features of anti-continuity and negative correlation; 4) annual precipitation has apparent abrupt change in 1989, and abrupt changes are also found in the spring, summer and autumn in 1994, 1979, and 1985, respectively, with no abrupt change in winter; 5) the variation period of annual and seasonal precipitation fluctuates in time scales of 22-29 a, 13 a, and 4-8 a, and the periodic change differs greatly in various scales.

Key words: precipitation variation, Bahe basin, Mann-Kendall test, R/S analysis, wavelet analysis