中文摘要：

针对水文时间序列的非平稳性,采用小波分析方法研究钱塘江河口年径流序列的近似周期及其变化趋势.在分析复Morlet小波函数基本特性的基础上,选用该小波对标准化径流序列进行小波变换,根据小波变换系数模与实部的时频分布以及小波方差图揭示钱塘江河口年径流过程伴随着21a左右的显著周期成分,预计在2008-2010年间,该河口仍将维持径流偏枯的趋势,而后才转入偏丰期.结合历年的实测水下地形资料,分析径流周期性变化与河口河床冲淤之间的关系.结果表明,两者关系密切,在径流偏丰期,河床冲刷河势顺直;在径流偏枯期,河床淤积河势弯曲.

英文摘要：

In accordance with the non-stationary hydrological time series,the wavelet method was adopted to analyze the periodic feature and the trend of the runoff in the Qiantang estuary.The complex Morlet function,whose basic characteristic was discussed,was selected to transform the standardized time-series of the annual runoff discharge.Based on the distribution of module and real of wavelet transform coefficients and wavelet variance,the prominent period of the annual runoff discharge in the Qiantang estuary is 21years approximately,and it is predicted that the trend of the annual flow is in the low flow period from 2008to 2010,and then the annual discharge is increase.Combined the observed topographical data,the relationships between the periodic variation of the runoff and riverbed deformation was analyzed.The results show there is a close relationship between them.The riverbed is scoured with straight alignment of river course during high flow period,and deposited with curved alignment of river course during low flow period.