基于EMD的黄河下游利津站年水沙量变化的多时间尺度特征

运用经验模态分解方法对黄河下游利津站1952~2009年的年水沙量的时间序列资料分别进行多时间尺度的分析，得到各自具有不同周期的波动分量以及趋势分量。研究结果表明：利津站年水沙量的变化过程具有复杂的多时间尺度特性，是各种波动成分共同作用的结果；年水量和年沙量变化过程均存在三个波动周期，且趋势项呈递减降低的态势，而各分量的波动周期大致相近；两者相同尺度下的分量之间具有显著的相关性，而不同尺度下的分量之间基本无相关性，揭示了水沙变化过程内在多时间尺度振荡结构和特征。

Multiple Time-scale Variation of Annual Runoff and Sediment at Lijin Station In the Lower Reach of Yellow River Based on EMD Analysis

The method of Empirical Mode Decomposition(EMD),a new multi-scale analytical method,is applied to the annual runoff and sediment at Lijin Station in the Lower Reach of Yellow River from 1952 to 2009,and different intrinsic mode functions and one residual function are obtained for each series.The results show that there is a complex multiple time-scale character in the series of annual runoff and sediment of Lijin Station.It is induced by the fluctuation components jointly.The annual runoff and sediment series have 3 fluctuation periods,both of which have nearly the same periods,and the residual function of the two series is degressive.The same time scale components of the two series have notable relativity,however the different time scale components have little relativity.Then,the intrinsic structure and character of multiple time-scale fluctuation of annual runoff and sediment series can be revealed.