潮沟系统水沙输运研究——以长江口崇明东滩为例

发布时间：2018-02-21 00:31

本文关键词： 长江口盐沼光滩潮沟泥沙水动力　出处：《海洋学报》2017年07期 　论文类型：期刊论文

【摘要】：本研究以崇明东滩2015年4月实测潮间带水沙数据为基础,分析了潮沟、盐沼及光滩的水沙特征,重点研究了潮沟系统及邻近潮滩潮周期内悬沙通量情况。结果表明:(1)潮沟表层沉积物比潮滩细,二者平均中值粒径分别为21.7μm和33.0μm,悬沙粒径由海向陆逐渐变小;(2)大、小潮沟潮周期内潮流均以往复流为主,垂向平均流速分别为15.4cm/s和34.6cm/s;盐沼界和光滩则以旋转流为主,平均流速分别为11.3cm/s和28.9cm/s;(3)潮沟中的高悬沙浓度出现在涨潮初期,最大可达7.5kg/m~3,而潮滩高悬沙浓度则出现在潮落潮中期和高水位时刻;大、小潮沟和盐沼界站涨潮阶段平均悬沙浓度大于落潮阶段,光滩站则相反。潮沟悬沙主要来自邻近水域,而潮滩悬沙则与滩面表层沉积物密切相关;(4)潮沟在潮周期内净输沙方向均指向滩地,大潮沟潮周期单宽净输沙量可达4.0t/m;盐沼界处垂直岸线和沿岸输沙强度相近,净输沙由海向陆,潮周期离岸输沙强度为1.0t/m;光滩沿岸输沙强度远大于垂直岸线输沙,光滩净输沙由陆向海。研究揭示了潮间带潮沟系统的强供沙能力以及研究区域光滩冲蚀,盐沼植被带淤积的动力地貌过程。
[Abstract]:Based on the measured water and sediment data of East Chongming Beach in April 2015, the characteristics of water and sediment in tidal trench, salt marsh and plain beach are analyzed. The suspended sediment fluxes in tidal trench system and adjacent tidal flat are mainly studied. The results show that the surface sediment of the trench is smaller than that of the tidal flat. The mean median particle size of the sediment is 21.7 渭 m and 33.0 渭 m, respectively, and the suspended sediment size gradually decreases from sea to land. In the tidal cycle, the tidal current is mainly reciprocating, and the vertical average velocity is 15.4cm / s and 34.6cm / s respectively, while the salt marsh boundary and beach are mainly rotating flow, the average velocity is 11.3 cm / s and 28.9 cm / s respectively) the high suspended sediment concentration in the trench appears in the early stage of the high tide. The maximum value is 7.5 kg 路m ~ (-1) 路m ~ (3), while the high suspended sediment concentration of tidal flat appears in the middle of tide fall and high water level, and the average suspended sediment concentration in high tide stage of large, small tide trench and salt marsh boundary station is higher than that in falling tide stage, whereas that in Guangtan station is opposite. However, the suspended sediment of tidal flat is closely related to the surface sediment of beach surface.) the direction of net sediment transport of tidal trench during the tidal cycle is directed towards the beach, the single width net sediment transport of tidal trench can reach 4.0 t / m, and the intensity of vertical shoreline and coastal sediment transport at salt marsh boundary is similar. The intensity of offshore sediment transport in the tidal cycle is 1.0 t / m, the coastal sediment transport intensity of Guangtan is much higher than that of vertical shoreline, and the net sediment transport of smooth beach is from continental to sea. The study reveals the strong sediment supply capacity of tidal trench system in intertidal zone and the erosion of plain beach in the studied area. Dynamic geomorphological process of deposition in salt marsh vegetation zone.
【作者单位】：华东师范大学河口海岸学国家重点实验室;
【基金】：国家自然科学基金项目(51320105005,41406094,41506105,41276080) 国家科技支撑计划课题(2013BAB12B05-02) 中国博士后科学基金面上资助(2016T90351)
【分类号】：P736.21

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