渭河流域径流序列变异检测与成因分析

Detection of the Abrupt Changes Point and Genetic Analysis for the Runoff Series of Weihe River

针对水文时间序列的非线性和非平稳性,采用Hilbert-Huang变换对渭河林家村水文站1960—2000年的年径流序列进行变异检测;同时对影响渭河流域径流变化的因素进行分析。首先通过EMD对原始径流序列进行分解,得到不同分量的固有模态函数和残余趋势成分。对EMD高频分量求一阶微分,取其模值,模值最大的点即径流时间序列的变异点。经过分析可知,渭河流域林家村站存在3个变异点,分别为1972年、1982年和1994年。结果表明:对于变化环境下高度复杂、非线性的径流时间序列,采用Hilbert-Huang变换方法能够准确有效地诊断时间序列的变异点,并有效揭示径流序列在不同阶段的动力学结构特征。

Accordinf to the nonlinear and non-stationary of the hydrolofical time series,Hilbert-Huanf transform was used to detect the abrupt chanfes point of the runoff series of LinJiacun Hydrometric Station of Weihe River from 1960 to 2000,at the same time the chanfe factors of Weihe River basin were analyzed. First,the different component of intrinsic mode function（ IMF）and residual trend components of the orifinal runoff se-ries were obtained by empirical mode decomposition,and then obtained the modulus of the first-order differentia of the hifh frequency component, which the biffest point of the modulus values was the mutation of the runoff time series. It could be concluded that there were three chanfe points in 1972,1982 and 1994 respectively after analysis. The results show that the Hilbert-Huanf transform method can accurately diafnosis time sequence variation point for hifhly complex of the chanfinf environment of nonlinear runoff time series and effectively reveals flow sequence in different phases of the dynamic structure characteristics.