抗差Vondrak滤波方法在内孤立波提取中的应用研究

声学多普勒流速剖面仪(ADCP)是对海洋内波监测的有效手段,但受到仪器本身和复杂的海洋环境噪声等影响,走航式ADCP记录的海流数据存在大量噪声,且混有流速异常值。为了进一步提高海洋内孤立波的提取精度与准确性,本文针对走航式ADCP海流数据特点引入IGG3方法的权函数因子,设计了一种抗差Vondrak滤波器,并与快速傅里叶变换、小波分析和滑动平均3种传统滤波方法进行对比,以验证抗差Vondrak滤波方法的有效性与优越性。研究结果表明,抗差Vondrak滤波方法不仅可以有效地滤除流速噪声,还可以自适应剔除海流观测数据中的异常值,由其提取出的内孤立波准确且各层水平流速清晰。因此,与传统滤波方法相比,抗差Vondrak滤波方法在内孤立波提取方面具有一定的优越性。

The application research of Robust Vondrak filtering method in extracting internal solitary waves

Acoustic Doppler Current Profiler (ADCP) is an effective way to monitor ocean internal waves. However, due to the influence of the instrument itself and complex ocean environment noise, there are a lot of noise and some abnormal velocity values in the velocity data recorded by ADCP. In order to further improve the extraction accuracy of internal solitary waves in the sea, the weight function factor of IGG3 method was introduced according to the characteristics of the shipboard ADCP velocity data, and the Robust Vondrak filter was designed. In order to verify the effectiveness and superiority of Robust Vondrak filtering method, it was compared with three traditional filtering methods: fast Fourier transform, wavelet transform and sliding average. The experimental results show that the Robust Vondrak filtering method can not only remove the flow velocity noise, but also effectively eliminate abnormal flow velocity values, so it has certain advantages compared with the traditional filtering methods. The Robust Vondrak filtering method can extract internal solitary waves accurately and the horizontal velocity of each layer is clear. It is a good method to extract internal solitary wave.