EMD-IVMD方法在验潮站水位序列降噪中的应用

Application of EMD and improved VMD in tide station data noise reduction

针对验潮站水位变化序列非线性、非平稳特点,采用一种基于优化参数的变分模态分解和经验模态分解相结合的降噪方法。该方法先经过EMD分解原始信号后,得到低频和高频信号两个部分,再采用IVMD方法处理高频噪声部分,最后将两部分有效低频信号重构作为最终降噪信号。采用1组模拟数据和4个验潮站实测水位序列数据进行实验,并采用信噪比和均方根误差评价降噪效果,结果表明,EMD-IVMD方法明显优于EEMD和传统的EMD方法,该方法在信噪比精度指标上分别提升1.67%和1.52%,在均方根误差精度指标上分别提升9.59%和13.51%,验证该方法的有效性和可靠性。

The noise in the water level sequence data of tide gauge stations is very complex and has the characteristics of nonlinearity and non-stationarity.The error of tide gauge, reference error, analysis error, and the influence of geophysical effects are all the reasons for the noise.Aiming at the noise problem, this paper proposes a noise reduction method based on the combination of variational modal decomposition and empirical modal decomposition based on optimized parameters.This method first decomposes the original signal through EMD to obtain two parts of low-frequency and high-frequency signals, then uses IVMD to process the high-frequency noise reconstruction part, and finally reconstructs the two parts of the effective low-frequency signal as the final noise reduction signal.This paper uses a set of simulated data and four tide gauge station measured water level sequence data to conduct experiments, and uses signal-to-noise ratio and root mean square error to evaluate the noise reduction effect.The results show that the EMD-IVMD method is significantly better than EEMD and traditional The EMD method.This method improves the accuracy of signal-to-noise ratio by 1.67% and 1.52% respectively, and improves the accuracy of root mean square error by 9.59% and 13.51% respectively, which verifies the effectiveness and reliability of the method.