不同海带生长季的桑沟湾潮流特征变化分析

Analysis on Tidal Current Characteristics During Different Kelp Growing Seasons in Sanggou Bay,China

基于桑沟湾海带非养殖季和养殖季的长时间观测数据,分析了不同养殖时期的潮位潮流调和要素、潮流垂向和水平空间分布变化规律,利用谱分析以及潮能通量的对比从能量角度进一步探究了不同海带生长阶段的养殖阻力对当地水动力环境的影响。在7月海带收获季,上层水体受到的养殖阻力最强,且落潮阶段的流速剖面在海带长度范围内(水深5 m以浅)出现了流速均匀分布的现象,相比4月生长旺盛季更为明显。通过潮流分层谱分析可知,半日分潮的功率谱密度的垂向变化是造成流速剖面变化的主要原因。养殖阻力的存在削弱了桑沟湾湾内的潮能传播,养殖季寻山至楮岛的潮能通量衰减是非养殖季的将近2倍。

Based on the long-term observations during kelp non-culture and culture season in the Sanggou Bay,harmonic constants of tidal level and tidal currents,vertical and horizontal spatial distribution of tidal current in different culture stages were analyzed.By means of power spectrum analysis and comparison of tidal energy flux,the influence of kelp culture resistance at different growth stages on local hydrodynamic environment were further studied.It shows that he culture resistance in upper water column is largest in July in kelp harvest season.The current velocity profile within kelp length range(shallower than 5 m)is uniform at ebb tide in July,and this is more obvious than that in April.The power spectrum analysis of vertically stratified tidal current showed that the vertical variation of the power spectrum density of half-diurnal tidal constituent was the main reason for shaping the velocity profile.In culture season,the propagation of tidal energy in the Sanggou Bay is weakened by culture resistance.The attenuation of tidal energy flux in culture season reaches nearly twice as much as that in the season without kelp.