江苏大丰潮滩悬沙级配特征及其动力响应
Characteristics of grain-size distributions of suspended sediment and its response to dynamics over the Dafeng tidalflat, Jiangsu coast in China
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摘要: 根据2002和2003年夏季在江苏大丰潮滩的现场观测资料,详细分析了悬沙级配的时空分布特征、影响因素及其对再悬浮、沉降和流速的响应.研究结果表明,悬沙颗粒较细,以粉砂为主,悬沙级配在潮周期内的变化模式有两种类型:一是稳定型,悬沙级配的时空(垂向和平面)变化很小;二是双峰型,悬沙级配的时空变化显著,粗细峰高度不断变化.再悬浮、沉降、涨潮时输入潮滩的悬沙和底质级配是影响悬沙级配的重要因子.再悬浮使粗颗粒悬沙的含量增加,悬沙与底质级配不断接近,沉降对悬沙级配的影响与再悬浮相反.再悬浮发生时悬沙级配对流速有明显响应.在没有再悬浮和沉降影响的情况下,潮滩不同部位、不同时间的悬沙级配趋于稳定和相同,对这种状态下的悬沙级配可称为背景悬沙级配,大丰潮滩背景悬沙级配的平均粒径为7μm.Abstract: On the basis of the measurement of suspended sediment at several sites over the Dafeng tidalflat in the summer of 2002 and 2003, the northern Jiangsu coast, the spatio-temporal characteristics of grainsize distributions of suspended sediment and its response to resuspension, settling process and tidal current velocity are analyzed.The results show that the suspended sediment is mainly composed of fine and very fine silt, and the mean grain-size is 7~13 m.On the basis of the in-situ measurement data, the spatiotemporal variation models of the grain-size distributions of the suspended sediment during the tidal cycle can be summarized into two types, one is the stability type when the variation is insignificant and the other is the double-peak type when the variation is remarkable.The main factors that influence the grain-size distributions of the suspended sediment are resuspension, settling process suspended sediment imported into tidal flats during the flood phase and the grain-size distributions of seabed sediment.The resuspension can increase the coarse particles content and the mean grain-size of the suspended sediment and cause the grain-size distributions of the suspended sediment close to the seabed sediment; the effects of settling process on the suspended sediment are opposite to those of the resuspension.When the resuspension occurs, the variation of the gain-size distributions of the suspended sediment in the lower part of water column can reflect the process clearly, the mean grain-size of the suspended sediment has good linear relationships with the current velocity.Without the effects of resuspension and settling process.the grain-size distributions of the suspended sediment is inclined to be stable and invariable during the measurement period over different parts of tidal flats, the mean grain-size of the background suspended sediment over the Dafeng tidalflat is 7 μm.
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O'BRIEN D J,WHITEHOUSE R J S,CRAMP A.The cyclic development of a macrotidal mudflat on varying time scales[J].Continental Shelf Research,2000,20:1 593-1 619. 朱大奎,柯贤坤,高抒.江苏潮滩沉积研究[J].黄渤海海洋,1987,4(3):19-28. 范代读,李从先,陈美发,等.长江三角洲泥质潮坪沉积间断的定量分析[J].海洋地质与第四纪地质,2001,21(4):1-6. KE Xian-kun,COLLINS M B,POULOS S E.Velocity structure and sea bed roughness associated with intertidal (sand and mud) flats and saltmarshes of the Wash,U K[J].Journal of Coastal Research,1994,10(3):702-715. COLLINS M B,KE Xian-kun,GAO Shu.Tidally-induced flow structure over intertidal flats.Estuarine,Coastal and Shelf Science[J].1998,46:233-250. 李占海,高抒,柯贤坤,等.江苏大丰潮间带粉砂滩的潮流边界层特征[J].海洋通报,2003,22(3):1-8. WHITEHOUSE R J S,BASSOULLET P,DYER K R,et al.The influence of bedforms on flow and sediment transport over intertidal mudflats[J].Continental Shelf Research,2000,20:1 099-1 124. 陈卫跃.潮滩泥沙输移及沉积动力环境[J].海洋学报,1991,13(6):813-821. 张忍顺.江苏省淤泥质潮滩的潮流特征及悬移质沉积过程[J].海洋与湖沼,1986,17(3):235-245. FRENCH C E,FRENCH J R,CLIFFORD N J,et al.Sedimentation-erosion dynamics of abandoned reclamations:the role of waves and tides[J].Continental Shelf Research,2000,20:1 711-1 733. STELDER B J.The effect of different hydrodynamic conditions on the morphodynamics of a tidal mudflat in the Dutch Wadden Sea[J].Continental Shelf Research,2000,20:1 461-1 478. 李伯根,谢钦春,夏小明,等.瓯江口南岸潮滩沉积动力过程的探讨[J].海洋学报,1994,16(2):86-94. 李占海.江苏大丰地区潮滩沉积动力过程[D].南京:南京大学,2003.22-26. 任美锷.江苏省海岸带和海涂资源综合调查[M].北京:海洋出版社,1986.40-43,224-225. 庄武艺,谢佩尔J.海草对潮滩沉积作用的影响[J].海洋学报,1991,13(2):230-239. 贾建军,高抒,薛允传.图解法与矩法沉积物粒度参数的对比[J].海洋与湖沼,2002,33(6):576-582. LINK A G.Textural classification of sediments[J].Sedimentology,1966,7:249-254. 李伯根,谢钦春,夏小明,等.椒江河口最大浑浊带悬沙粒径分布及其对潮动力的响应[J].泥沙研究,1999,(1):18-26. WHITEHOUSE R.Observations of the boundary layer characteristics and the suspension of sand at a tidal site[J].Continental Shelf Research,1995,15(13):1 549-1 567. MILLER M C,MCCAVE I N,KOMAR P D.Threshold of sediment motion under unidirectional currents[J].Sedimentology,1977,24:507-527. Van RIJN L C.Sediment transport:Part Ⅱ.Suspended load transport[J].Journal of Hydraulic Engineering,1984,110(11):1 613-1 641. -
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