The observed currents in summer in the Bohai Sea

A harmonic method was used to analyze the tidal currents observed in summer at 11 stations made from 1996 to 2001 in the Bohai Sea,China.Data was compared among different instruments and intervals.Elliptic elements were calculated based on harmonic constants,of which vertical distributions of the maximum speed and rotation direction were discussed for understanding the characteristics of diurnal and semi-diurnal tidal current components.The results indicate that the maximum speed of M2 tidal current component is much larger than that of K1; the rotation direction of M2 tidal current constituent is clockwise in the central part of the Bohai Sea and in the Laizhou Bay,but anticlockwise in the Liaodong Bay and Bohai Bay.For K1 tidal current constituent,it is clockwise in the central Bohai Sea but anti-clockwise in the Laizhou Bay and Liaodong Bay.The tidal currents in most stations in the Bohai Sea were regular semidiurnal except for those in the central Bohai Sea,being irregular semidiurnal.