以沂沭河流域为研究区, 根据流域内 7 个代表性雨量站 1954 年- 2010 年降水资料, 采用自相关系数、 频次分 析法、 累积距平法、 小波分析法、 Mann 2Kendall 法、 R/ S 法等方法分析了流域内降水演变特征。结果表明: 各站年降 水量之间存在显著的正相关性, 多年平均降水量从北向南逐渐增加, 降水年际变化幅度从北向南逐渐减小; 降水偏 丰水年、 平水年出现频次最大; 降水年际变化经历了 3 个丰水段、 1 个平水段和 4 个枯水段; 各站年、 汛期、 非汛期降 水变化的第一周期为 12 a、 12 a 和 5 a, 第二周期为 16 a、 17 a 和 5 a, 第三周期为 4~ 5 a、 4~ 5 a、 3 a 或 10 a; 各站年、 汛期、 非汛期降水多呈不同程度的减少趋势, 未来降水多呈较强的下降趋势。

According to the precipitation data of seven representative precipitation stations in the Yishu River Basin from 1954 to 2010, the variation characteristics of precipitation were analyzed using the correlation coefficient, frequency analysis method, ac 2 cumulative anomaly method, M orlet wavelet method, M ann2Kendall method, and R/ S method. T he results showed that ( 1) there is a significantly positive correlation between the precipitation data series of each station, and the average annual precipitation in2 creases gradually from north to south, while the annual variation magnitude of precipitation decreases from north to south; (2) the occurrence frequencies of partial wet year and normal year are the highest; (3) the variations of annual precipitation have un2 dergone three wet phases, one normal phase, and four dry phases; ( 4) the first characteristic time scales of annual precipitation, flood season precipitation, and non2flood season precipitation are 12 a, 12 a, and 5 a, respectively, the second characteristic time scales are 16 a, 17 a, and 5 a, respectively, and the third characteristic time scales are 4~ 5 a, 4~ 5 a, and 3 or 10 a, respectively; and (5) annual precipitation, flood season precipitation, and non2flood season precipitation have a decreasing trend, and precipi 2 tation of most stations will have a strong decreasing trend in the future.

国家自然科学基金项目( 50979023) ; 水利部公益性科研专项( 201201026)