东海定点连续观测站海流资料分析

Current analysis at a continuous observation station in the East China Sea

采用快速离散傅立叶变换(FFT)、潮流调和分析以及小波(wavelet)变换等方法,分析了一个位于大陆架边缘海域定点连续观测站上的海流记录。FFT结果表明在该海域以半日周期潮流和日周期潮流为主。潮流调和分析结果表明垂向各个潮流分量受上下边界层影响存在显著的变化,余流的东西分量在观测时段内发生了一次转向。用小波变换对海流观测的高频分量进行了分析,分离出10～20min周期的高频内波信号,U方向和V方向的信号在不同的时间有所差异。

Fast Fourier Transform (FFT), Tidal Current Harmonic Analysis (TCHA), and Wavelet Transform (WT) are used to analyze current observations in the continental shelf sea area. FFT results show semidiurnal tides and diurnal tides dominate the current movement. TCHA shows every constituent of tides has distinct vertical structures under the influence of upper and bottom boundary layers. The residual current makes an obvious diversion during the observation period. High frequency current part analyzed by WT reveals some internal wave signals, whose period is about 10～20 minutes. The high frequency signals of U-component and V-component are different during different time periods.