Sediment resuspension and implications for turbidity maximum in the Changjiang Estuary
Sediment resuspension and implications for turbidity maximum in the Changjiang Estuary
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DOI：
10.1016/s0025-3227(98)00003-6
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发表时间：
1998-07
期刊：
影响因子：
2.9
通讯作者：
Jiufa Li;Chen Zhang
中科院分区：
文献类型：
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作者：
Jiufa Li;Chen Zhang
对长江口河口粘性沉积物性质和运移的比较研究表明，悬浮泥沙浓度（SSC）的增加主要是由于河口坝河段底部沉积物的再悬浮以及变形潮汐和强潮流的影响。盐度入侵和垂直重力环流导致“捕获”从河流和海洋流入的悬浮沉积物。因此，最大浊度 (TM) 是通过累积物质的局部再悬浮和河床侵蚀来实现的。长江口的TM不仅具有相对于邻近河段较高的SSC，而且还具有较高的冲刷量。泥沙的输送非常重要。絮凝作用增加了悬浮沉积物的沉降速度。弱流时期的大量沉降常常导致流体泥浆的形成。 TM 与口栏局部重合。采用分裂法分析TM中悬浮泥沙的输送情况。结论是，影响因素包括平流项和潮汐抽吸。北航道以平流输送为主，北支和南航道以潮汐抽吸为主，北航道处于中间状态。
A comparative study on the properties and transport of the cohesive sediments in the mouths of the Changjiang Estuary proves that the suspended sediment concentration (SSC) is principally enhanced by the resuspension of bottom sediment in the mouth-bar reach, coupled with the deformed tidal wave and strong tidal current. Salinity intrusion and vertical gravitational circulation lead to the ‘trapping’ of the suspended sediment inflowed from the river and the sea. The turbidity maximum (TM) is therefore delivered by the local resuspension of the accumulated materials and bed erosion. The TM in the Changjiang Estuary is marked not only by its high SSC relative to the adjacent reaches, but also by the high wash-load content. Transport of sediment is very important. Settling velocity of suspended sediment is increased by flocculation. The massive settling during weak current periods often gives rise to the formation of fluid mud. The TM coincides locally with the mouth-bars. The transport of suspended sediment in the TM is analysed by using a splitting method. It is concluded that the contributing factors consist of advective terms and tidal pumping. Advective transport is dominant in the North Channel and tidal pumping predominate in the North Branch and South Passage, and the North Passage is in an intermediate situation.