| 潮沟系统水沙输运研究——以长江口崇明东滩为例 |
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| 引用本文： | 谢卫明,何青,王宪业,郭磊城,郭超.潮沟系统水沙输运研究——以长江口崇明东滩为例[J].海洋学报,2017,39(7):80-91. |
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| 作者姓名： | 谢卫明 何青 王宪业 郭磊城 郭超 |
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| 作者单位： | 华东师范大学 河口海岸学国家重点实验室, 上海 200062 |
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| 基金项目： | 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）。 |
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| 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21.7 μm和33.0 μm，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15.4 cm/s和34.6 cm/s；盐沼界和光滩则以旋转流为主，平均流速分别为11.3 cm/s和28.9 cm/s；（3）潮沟中的高悬沙浓度出现在涨潮初期，最大可达7.5 kg/m3，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4.0 t/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1.0 t/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。
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| 关 键 词： | 长江口 盐沼 光滩 潮沟 泥沙 水动力 |
| 收稿时间： | 2016/9/27 0:00:00 |
| 修稿时间： | 2017/1/11 0:00:00 |
Hydrodynamic process and sediment transport in a tidal creek system over the Easten Chongming Island, Yangtze Estuary |
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| Xie Weiming,He Qing,Wang Xianye,Guo Leicheng and Guo Chao.Hydrodynamic process and sediment transport in a tidal creek system over the Easten Chongming Island, Yangtze Estuary[J].Acta Oceanologica Sinica (in Chinese),2017,39(7):80-91. |
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| Authors: | Xie Weiming He Qing Wang Xianye Guo Leicheng and Guo Chao |
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| Institution: | State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China |
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| Abstract: | To speculate about the hydrodynamic process and sediment transport within the intertidal zone, we conducted a two-day survey in the Eastern Chongming Island in April, 2014 during a spring tide. Four tripods were deployed in three main morphological domains:one in the salt marshes, one in the mudflats and two in the tidal creeks. Our results show that:(1) the median particle size of surficial sediment in the creeks is 21.7 μm and is finer than that in the salt marshes and mudflats which is 33.0 μm. The particle size of suspended sediment decreases landward; (2) the dominant currents are rectilinear currents in the tidal creeks while are often rotational flows in the flats. The average vertical velocity in the lateral, creek, salt marsh, and mudflat is 15.4 cm/s, 34.6 cm/s, 11.3 cm/s, and 28.9 cm/s, respectively; (3) the highest suspended sediment concentration appears in the early flood periods in the tidal creeks while occurs during slack water or in the middle of the ebb periods in the flats. The suspended sediment in the tidal creeks mostly derives from adjacent sea rather than resuspension which is the main suspended sediment source in the flats; (4) over a tidal cycle, net landward sediment transport is observed in the creeks and the average sediment flux per tidal cycle could be 4.0 t/m. There is also a net import of sediment with 1.0 t/m per tidal cycle driven through the salt marsh. On the contrary, the net sediment flux in the mudflat is seaward along the creek and the dominant sediment transport in the mudflat is perpendicular to the creek rather than along the creek which the lateral, creek and salt marsh are. Our results also indicate that the salt marshes experience deposition while the mudflats are eroded in our study site. |
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| Keywords: | Yangtze Estuary salt marsh mudflat tidal creek sediment hydrodynamics |
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