石羊河下游年径流序列的变异点分析

Analysis on aberrance point of annual runoff serials in the downstream of Shiyang River

为了较准确地判断人类活动对石羊河径流的干扰点，利用重新标度极差分析法（RescaledRangeAnalysis），对下游红崖山水库1956～2000年的入库径流序列进行了分析。结果表明，径流序列变异年份为1977年。以其为分界点的前后两个序列的统计特征值及回归方程均具有明显的差异，这与石羊河流域水土资源开发利用情况基本一致，说明变异点分析结果符合实际。由此可见。自从20世纪70年代后期，自然条件巳不是影响石羊河下游径流变化的主要因素，而上中游人类活动对径流起着主导作用。

In order to exactly determine the disturbance point of human activities to the runoff in Shiyang River, this paper analyzed the serial of runoff into the Hongyashan Reservoir in the lower reaches from 1956 to 2000 by R/S analysis （Rescaled Range Analysis）. The results showed that, the aberrance year of the runoff sequence was 1977. There were significant differences between both the statistical eigenvalues and the regressive equations of the two sequences divided by 1977. This approximately accorded with the status of exploitation and use of water and land resources in the Shiyang River basin, which showed that the analysis result of the aberrance point was reliable. Thus it could be seen that since later 1970s,the natural conditions have not been the main factor that influences the change of runoff in the downstream of Shiyang River, and human activities in the upper and middle reaches have produced a dominant effect on the runoff.