1950~2005年大通河流域径流变化特征及影响因素

以大通河流域享堂水文站1950~2005年实测径流数据为基础,综合运用趋势分析、累积距平、R/S分析、Morlet小波分析、降水-径流深度双累积曲线等数理统计方法,研究了大通河流域径流的年内分配、年际变化和周期振荡特征、并定量分析了气候因素和人类活动因素对径流变化的影响。结果表明:（1）大通河径流年内主要集中在510月,占年径流总量的82%左右。1950~2005年,大通河流域年径流呈微弱减少趋势,递减率为-0.55×10⁸m³/10a（R2=0.025,P=0.249）,Hurst指数为0.58,表明未来一段时间内径流仍可能呈减少趋势;（2）1950~2005年,大通河流域年径流在27a时间尺度上周期震荡明显,经历了"多-少-多-少-多-少-多"7个循环交替;（3）大通河流域降水-径流深度双累积曲线在1994年发生显著偏移,1994年之前径流变化主要受降水影响,1994年以后,径流变化主要受人类活动影响。

Variation Characteristics of Runoff and Its Driving Forces in Datong River Basin from 1950 to 2005

Responses of water resources to human activities and climate factors, which is the basis to explore the hydrological processes and scientific management of regional water resources, has attracted more and more attentions in water resources research in recent years. Based on runoff data measured by Xiangtang hydroligical station in the Datong River Basin from 1950 to 2005, with temperature and precipitation time series, runoff change characteristics were analyzed by using linear tendency, 5 years moving average, accumulation anomaly, wavelet analysis methods. The effects of precipitation change and human activities on runoff were also studied quantitatively using double mass curve for annual rainfall stream flow. The results show that: (1) The annual runoff of the Datong River Basin was mainly contributed by those occurred from May to October with a proportion of 82.2%. Regression analysis shows that the Datong River Basin''s runoff slightly decrease with time at a rate of -0.55·108 m3 /10a (P=0.249). The Hurst index is 0.58, which indicates that the decreasing trends of runoff in the Datong River Basin will continue in the future. (2) In recent 60 years, the Datong River Basin has different oscillation periods. In the time scale of 27a, the oscillation is mostly significant. The annual runoff will decrease after the year 2012, and will end up in the year 2020. (3) Using relational analysis and double mass curve analysis, we have obtained that mean annual runoff in the Datong River Basin is closely related to the annual rainfall before the year 1994. However, the human activities have become the main factor that causes the runoff decrease in the Datong River Basin after the year 1994 compared with annual rainfall. This paper considered the precipitation and human activities in driving forces analysis. In fact, evapotranspiration, LUCC and other factors should also be included. Therefore, the specific influencing factors of runoff changes need to be further studied.