浙江瓯飞浅滩潮位、悬沙及水沙通量空间分布特征研究

Tidal level,suspended sediment concentration,and water and sediment fluxes in the Oufei shoal,Zhejiang province

本文主要依据2010年10月浙江瓯飞浅滩一个潮周期内的潮流和悬沙浓度资料,对浙江瓯飞浅滩淤泥质海岸的潮流和悬沙特征进行了分析研究。结果表明:(1)瓯飞浅滩的潮流具有明显的往复流性质,涨潮往西北向,落潮流往东南向;潮流在平面分布上是河口流速大于开敞海域的流速,如测站1的大潮涨潮平均流速是0.93 m/s,测站5的大潮涨潮平均流速是0.36 m/s;潮流在垂向分布上逐步减少,表层最大,底层最小;(2)悬沙浓度在平面分布具有明显差异,河口区的悬沙浓度最大,开敞海域的悬沙浓度小;垂向上,底层的悬沙浓度大于表层的悬沙浓度,悬沙浓度的垂线分布大致呈现出抛物线、混合线型以及斜线型等三种类型;(3)瓯飞浅滩的单宽输水输沙具有复杂的时空变化,但是总的趋势是:河口附近是净向海输运,而外海的净输运方向是向陆输运。

This study conducted hydrological observations of a tidal period in the Oufei shoal,China,in October 2010 to analyze the characteristics of the tidal current and suspended sediment concentrations.The results show that(1)the current in the Oufei shoal exhibits a clear reversing trend;the flood current is northwestward,whereas the ebb current is southeastward.Moreover,an obvious spatial difference is observed in the tidal current in this area,i.e.,values are higher in estuaries than in open areas.For example,the average velocity of the flood tide during the spring tide is 0.93 m/s at station No.1,but 0.36 cm/s at station No.5.In the vertical direction,the maximum and minimum tidal current is on the surface layer and bottom layer,respectively.(2)There is a clear spatial difference in the suspended sediment concentration(SSC).The maximum and minimum SSC are observed in the estuary and on the open coast,respectively.Furthermore,the SSC at the bottom is greater than that at the surface.The vertical distribution of SSC takes the approximate form of a parabola,mixed linear,and slash-type.(3)The spatial and temporal water discharge and suspended sediment fluxes in the Oufei shoal are complex;however,the total trend reveals net seaward transport in estuaries and net mainland transport on the open coast.