The Periodical Analysis of the Danjiangkou Reservoir Inflow Based on the Morlet Wavelet

The waveform of the Morlet wavelet is similar to the form of streamflow, and there is direct correlation between the scale and the period. The Morlet wavelet is a complex wavelet, so it is able to reflect the time-frequency localization characteristics of the time sequence more realistically than the real wavelet. In this paper, a novel, rapid and practical method of non-orthogonal wavelet transform is used, and the derivation of the method is given. The Morlet wavelet is used to analyze the variation of the Danjiangkou Reservoir inflow, revealing the multi- scale fluctuation in and the law of periodical variation. The result shows that the inflow series have two periods (9 years and 24 years). The periodical curves of 9 years and 24 years simulated according to the real part of the wavelet coefficients are in good agreement with the actual data affected by the random components. The research result provides a technical support for the water resources development in the Hanshui River and the South-to-North Water Diversion plan.