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将小波变换应用到研究流域径流与含沙量的变化特性,采用db3小波对标准化径流与含沙量序列进行多分辨率分析,研究径流与含沙量变化的趋势性;选用复Morlet小波绘制出小波方差图,分析径流过程与含沙量过程存在的周期性。以崖羊山水电站所在的李仙江流域为例,针对电站坝址断面的月平均流量与含沙量序列进行小波分析,从低频重构序列的结果中可以看出该流域径流含沙量趋势。根据小波方差图可以看出,崖羊山水电站所在流域径流过程与含沙量过程存在非常接近的显著周期,均为2年左右,且两者变化周期具有同步性。表明小波分析是研究非平稳随机时间序列的有效方法。
Wavelet transform is applied to study the variation of runoff and sediment concentration. The multi-resolution analysis of runoff and sediment concentration is carried out by db3 wavelet to study the trend of runoff and sediment concentration. Wavelet variance plot to analyze the periodicity of runoff process and sediment concentration. Taking Li Xianjiang basin where Yaksamsang Hydropower Station is located as an example, wavelet analysis is performed on the monthly average flow and sediment concentration series of dam site cross sections. From the results of the low frequency reconstruction sequence, the runoff and sediment concentration trends in this basin can be seen. According to the wavelet variance diagram, we can see that the runoff process and sediment concentration in the basin where the Yayushan Hydropower Station is located are very close to each other, all of which are about two years old, and the cycle of the two is synchronous. It shows that wavelet analysis is an effective method to study nonstationary random time series.