党河水库入库径流量变化特征及趋势分析

Trend Prediction and Characteristics of Runoff Variation into the Danghe Reservoir

根据党河沙枣园水文站历年观测数据 ,利用模比系数定级分类和波谱分析等方法 ,对党河水库入库径流的年际变化特征进行了分析研究 ,发现多年变化过程大致经历了 3个枯水期、3个平水期和 3个丰水期。如以 10a为一个代表段来观察 ,5 0和 6 0年代为枯水段 ,70和 90年代为平水段 ,80年代为丰水段。总体而言 ,党河水库入库径流量枯水年、丰水年出现的机率大体相当 ,而平水年出现的机率相对较小。进一步分析发现 ,党河水库入库径流过程存在着 2～ 3a、6a、10～ 11a和 2 2a的变化周期 ,其中以 6a、10～ 11a和 3a的周期最为显著。这些周期的存在有明确的物理意义。在以上分析研究的基础上 ,采用灰色系统理论建立了残差序列周期修正GM (1,1)模型 ,对党河水库入库径流未来的变化趋势进行了研究。结果表明 ,本世纪开始的若干年内 ,随着天气系统的变化引起的祁连山区西部降水量的增加 ,党河水库入库径流量将呈现一个缓慢的上升趋势 ,预计这期间的年平均流量将略高于多年平均值。

Based on the historical records measured from the Shazaoyuan hydrological station on Danghe river, the annual variation characteristics of the runoff into the Danghe reservoir have been studied by using the methods of Frequency Factor Ranking Classification and Spectrum Analysis. In general, the processes of multi\|year runoff variation included 3 low water periods, 3 normal water periods and 3 high water periods. If at a decade scale, 1950s and 1960s were low water stages, 1970s and 1990s were normal water stages and 1980s were high water stages. Generally speaking, the appearing probability of low water and high water was similarly more, but that of normal water relatively less. Further, there were the 2～3 years, 6 years, 10～11 years and 22 years variation periods in the runoff processes into the reservoir, especially the 6 years, 10～11 years and 3 years were more evident. Based on the above analysis, the GM(1,1) model of residual error series with modified period was built up with the Gray System Theory, by which the variation trend of the runoff into the reservoir in future is predicted. The research results show that the runoff will increase smoothly and the annual mean will be slightly greater than the multi\|year average in the early some years of 21 Century due to the precipitation will be increased in the west of Qilian mountain that resulted from the change of weather system.