中文摘要：

中小型入海河口由于数量众多、分布广泛,其沉积动力学特征对于河口区的地貌环境演化等具有重要意义.新洋港河口是江苏淤泥质平原海岸上的典型中小型建闸河口,本文通过在新洋港河口进行的高精度三船同步现场观测,研究了河口的悬沙特征及沉积物对再悬浮作用的响应状况.结果表明,潮周期内悬沙浓度变化显著,涨潮及开闸放水期间悬沙浓度较大,最大平均悬沙浓度达1.45g·L^-1;而在其它时间段内悬沙浓度较小,从口门至闸门悬沙浓度有逐渐增大趋势.潮周期内典型时刻悬沙垂向分布符合＂L型＂分布特点,表、底层悬沙浓度差异显著.在有径流下泻期间,悬沙浓度垂向变化较为均匀,水体混合作用显著.悬沙平均粒径介于5～10μm;悬沙组分以粉砂为主,平均含量在70%以上.闸下及入海口区域再悬浮作用显著,最大再悬浮通量为10-4～10^-3 kg·m^-2·s^-1,从口门至河闸呈递减趋势;同时,悬沙出现粗化现象,砂组分含量增加.

英文摘要：

Characteristics of sediment dynamics in many small and medium sized estuaries have great significance for geomorphologic evolution.Xinyanggang Estuary is a typical small and medium sized estuary with sluice gate which locates on the muddy coast of Jiangsu Plain.This article studies the characteristics of suspended sediment and its response to sediment resuspension through the data from field observation of three mooring ships in Xinyanggang Estuary.The result shows that the suspended sediment concentration（SSC）changes significantly during tides,SSC dur-ing ebb tides and the opening of tidal sluice is higher than other periods,and increases gradually from estuary to the tidal sluice,and the highest average SSC reaches to 1.45g·L^-1.The vertical distribution of SSC during typical time of tides keeps with‘L type＇,which the SSC between surface and bottom differentiates greatly.The water mixes well and vertical SSC changes evenly during the period of fresh water runoff.The average grain size of suspended sediment ranges from 5μm to 10μm,and the main component is silt with an average percentage higher than 70.There exists bottom sediment resuspension during tides and the highest resuspension flux ranges from 10-4kg·m-2·s-1 to10^-3 kg·m^-2·s^-1,which decreases gradually from the estuary to the tidal sluice.The sediment grain size coarsens differently during the resuspension and the content of sand would increase in the component.Part of the suspended sediment of station S1 and S3comes from bottom sediment resuspension while with that derives from advection transport in station S2.