大伙房水库流域降水及径流变化特征分析

Variation characteristics analysis of pecipitation and runoff in Dahuofang reservoir basin

采用五点滑动平均法、趋势系数法、Mann-Kendall趋势检验法和方差分析法对大伙房水库流域1951-2006年年降水、入库年径流及天然年径流序列进行了分析。结果表明：三者变化趋势及周期以1980年为转折点呈阶段性变化。1980年以前均呈明显下降趋势并体现出4a的变化周期，年降水序列下降趋势及周期性较为显著；1980年以后均体现出10～11a的变化周期，入库年径流序列周期性相对明显，但年降水及入库年径流序列呈微弱的上升趋势，天然年径流序列呈微弱的下降趋势；1980年以后多年平均径流系数降低。分析其原因，降水变化主要源自气候变化，径流变化与降水、蒸发、下垫面变化及人类活动等影响因素有关。上述分析可为未来水情预报及水资源合理利用提供参考。

The annual precipitation, reservoir inflow and crude runoff data of Dahuofang reservoir basin in the past 60 years were analyzed by methods of five dots average slippage, trend coefficient, Mann-Kendall test and variance analysis. The results show that： their trend and period variation is staged and the year of 1980 is the turning point. Before the year of 1980, all of these decreased obviously and incarnated a 4-year variable cycle, the decreased trend and periodicity of precipitation was the most remarkable. After the year of 1980, all of them incarnated a 10-11 year variable cycle. The periodicity of reservoir inflow was reversely remarkable,for both precipitation and reservoir inflow increased rarely, but the crude runoff decreased faintly. The mean annual runoff coefficient decreased after the year of 1980. The causes of above-mentioned phenomena were analyzed as follows： The precipitation variance was derived from climate change, runoff variance was related to precipitation, evaporation, underlying surface variation and human activities etc. The above-mentioned analysis could offer reference for hydrological forecast and water resources utilization.