| 摘要: |
| 长江口最大浑浊带是陆海交汇的核心区域，其航槽是扼海-河联运的咽喉，悬沙峰的涨落潮周期变化深刻影响航槽的稳定性。本文利用长江口南槽上、中、下段3个站点枯季小潮和大潮的流速、盐度、悬沙平均粒径和悬沙浓度的实测资料，分析最大浑浊带悬沙峰特征及其动力机制。发现：流速和滩槽交换增强导致大潮平均悬沙浓度比小潮增加了0.78—1.97倍，絮凝也导致憩流底层悬沙浓度增加8%左右，但流速和絮凝与悬沙浓度的关系均非线性。大小潮盐度梯度与底层悬沙浓度关系呈现高线性相关关系，表明盐度梯度强化或突变是泥沙再悬浮形成悬沙峰的主要动力。 |
| 关键词: 絮凝 盐度梯度 悬沙峰 长江口 最大浑浊带 |
| DOI：10.11693/hyhz20171000273 |
| 分类号:P333 |
| 基金项目:国家自然科学基金项目，41671007号；国家重点研发计划项目，2016YFA0600904号。 |
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| HYDRODYNAMICS OF SSC PEAK IN DRY SEASON OF THE SOUTH PASSAGE OF CHANGJIANG RIVER ESTUARY |
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AI Wei1, LI Mao-Tian1,2, LIU Xiao-Qiang1, LI Wei-Hua1, NIU Shu-Jie1, TONG Meng1
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1.State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China;2.Institute of Eco-Chongming, East China Normal University, Shanghai 200062, China
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| Abstract: |
| The maximum turbidity zone in the Changjiang (Yangtze) River estuarine is a key zone of land-ocean interaction. The river channels are throat of transportation between sea and river, and the evolution of the channels is closely hinged on the hydrodynamics of high-concentration suspended sediment. Based on in-situ measured data of flow velocity, salinity, and the size and concentration of suspended sediment at three stations in the South Passage in the estuary during the dry season, we analyzed the characteristics and hydrodynamics of SSC (suspended sediment concentration) peak in the maximum turbidity zone. The results indicate that the SSC increased 0.78-1.97 times from neap to spring due to the enhancement of flow velocity and sediments exchange between channel and shoal, and the fine sand flocculation increased the SSC peak during the slack tide, but the correlations of flow velocity and SSC, the particle size, and SSC all are nonlinear. In addition, the salinity gradient and SSC are correlated each other highly and linearly, demonstrating that an abrupt change of salinity gradient is the intrinsic and dynamic factor of sediment re-suspension and the formation of the SSC peak. |
| Key words: flocculation salinity gradient SSC peak the Changjiang (Yangtze) River estuary maximum turbidity zone |
