摘要
In order to explore long-term evolution rule and future trend of runoff time series, and exactly detect its tendency and long-range correlation characteristics, runoff data covering 1952–2012 from 3 stations across the upper Fenhe River basin were analyzed. The moving average method, Empirical Mode Decomposition (EMD) method and Mann-Kendall (M-K) trend test method were simultaneously applied to analyze the trend characteristics firstly. Then Rescaled Range analysis (R/S) and Detrended Fluctuation Analysis (DFA) methods were employed to research the long-range correlation characteristics and length of non-periodic cycle of hydrological time series, they can systematically detect and overcome non-stationarity at all time scales. Finally, predict the future trend by combining the trend characteristics with the long-range correlation characteristics and length of non-periodic cycle. The results illustrate the annual runoff series is non-linear, non-normal time series, and have 10 years non-periodic cycle length and noticeable descending trend. This descending trend will continue in a period time of future.