摘要：The ocean currents during the periods of spring, middle and neap tides at six stations near Dafeng in Jiangsu Province are observed, the tidal current characteristics in the survey area are discussed, and the quasi-harmonic analysis is carried out. The harmonic co nstants and elliptical elements of six main tidal components, O1, K1, M2, S2, M4 and MS4, are obtained. The north component of the diurnal current and semidiurnal current amplitudes at the observation stations are larger than the East component. Among the tidal pattern coefficients of each station, the discriminant coefficients of tidal current types at each level are less than or equal to 0.5, which belongs to the normal half-day tidal current. The main form of tidal current movement at each station is the recirculation in the past. Most stations' tidal currents rotate counterclockwise. The maximum possible velocity of tidal current in the survey area is 235.7cm/s, which appears on the surface of B6 station, and its direction is 357 degrees. The maximum possible migration distance of water particle points in the survey area is between 14454.4 and 36042.7 m. The residual current of each station during observation period is obtained by quasi-harmonic analysis. The vector diagram of residual current is drawn, and the residual current of each station layer is analyzed. During the spring tide period, the observed residual current velocities in each layer of each station ranged from 3.4 to 22.7 cm/s, in the middle tide period ranged from 8.9 to 23.5 cm/s, and in the neap tide period ranged from 0.8 to 20.9 cm/s. During the observation period, the maximum residual current velocities appeared in the surface layer of B4 station and flowed to 277 degrees, while the vertical residual current velocities gradually decreased from the surface to the bottom, and the flow direction was basically identical.
关键词：Tidal current; Quasi-hannonic Elliptic factors; Dafeng; Jiangsu province; Residual current
