三门湾外海的潮汐和潮流特征

针对2009年5月-7月三门湾外海D8和D9两个站位布放的防渔网底拖锚系ADCP连续观测获取的流速资料和水位资料,采用调和分析和功率谱分析等研究方法,分析了该海域的潮汐和潮流特征,结果显示:该海域潮汐类型为正规半日潮,近岸的D9站浅水分潮比离岸的D8站显著,潮汐呈现出回归潮特征。三门湾外海潮流半日分潮能量最大, 各层潮流呈现出旋转流性质;椭圆率随水深增加;M₂、K₁分潮流最大流速均在次表层最大;最大分潮流速发生时刻底层比中、上层提前约半小时;该海域潮流的半日分潮流以正压为主,全日分潮流则表现出较为明显的斜压性。

Characteristics of the tide and tidal current off the Sanmen Bay

Based on the successive data of sea level and current velocity profiles obtained by two bottom-moored Acoustic Doppler Current Profilers (ADCP) from May to July of 2009 at D8 and D9 stations off the Sanmen Bay, the characteristics of tide and tidal current were investigated with power spectral analysis and harmonic analysis. The results show that the tide is regular semi-diurnal tide, shallow water tides at inshore area of D9 station is much more significant than that at offshore area of D8 station, and that the tide presents the characteristics of tropical tide. The semi-diurnal tidal currents off the Sanmen Bay are the strongest constituents, the tidal currents at different layers have the feature of rotary currents with the ellipticity increasing with depth, and the maximum velocity of both M₂ and K₁ constituents appears in subsurface. The occurrence of the maximum current in the bottom layer is about 30 minutes ahead of that in the middle and surface layers. The semidiurnal constituent in this area is mainly barotropic, while the diurnal one is of baroclinic feature.