基于小波分析的黄河上游水沙多时间尺度特征

Multi-time Scale Characteristics of Runoff and Sediment Series Based on Wavelet Analysis in the Upper Reaches of Yellow River

采用小波分析方法及相关理论,以黄河上游唐乃亥站53 a(1957—2009年)径流与输沙序列为例,初步分析并定量描述随序列长度变化时水沙时间序列主周期值的变化规律和特征。由于受降水等多种因素的影响,同一序列的不同长度、同一序列不同时期的相同长度及不同序列相同长度的主周期都有所不同。在此基础上,进一步研究了53 a长度的水沙序列多尺度精细结构。结果表明,黄河上游径流与输沙序列具有多尺度振荡的特点,存在着年际尺度和年代际尺度的周期变化规律,年径流序列的主周期为23 a和8 a,春季径流序列的主周期依次为5 a、24 a、8 a和15 a,年输沙序列的主周期为8 a和18 a,春季输沙序列的主周期依次为8 a、18 a和4 a。

The runoff and sediment change was affected by the natural factors and human activities,has the nonlinear and non-stationary characteristics. Wavelet analysis is a harmonic analysis method,not only inherited the traditional spectrum analysis method of joint time-frequency analysis,but also realized the time-frequency localization of two domains. It is advantageous to the multiple time scale variation characteristics analysis of hydrological time series,such as point mutation,and has the superiority in data processing analysis and calculation of hydrology and water resources. Based on the runoff and sediment data from 1957 to 2009 of Tangnaihai station of the Upper Reaches of Yellow River,the variation rule and characteristics of runoff and sediment series main period value with different series length were analyzed preliminarily and described quantitatively by wavelet analysis method and relative theory. As the effect of various factors,such as precipitation and so on,the main period of different length in same series,identical length of different period in same series and identical length in different series were different. On the basis of the above analysis,we analyzed the multi-time scale fine structure of runoff and sediment series for 53 years. The results showed that the remarkable multi-scale of wave energy oscillation and the periodic variation of interannual and decadal scales exist in both flow and sediment series of Upper Reaches of Yellow River. Annual runoff series have main periods of 23-year and 8-year. Spring runoff series have main periods of 5-year,24-year,8-year and 15-year. Annual sediment series have main periods of 8-year and 18-year. Spring sediment series have main periods of 8-year,18-year and 4-year.