地理学报 ›› 2012, Vol. 67 ›› Issue (9): 1269-1281.doi: 10.11821/xb201209011

• 河口海岸 • 上一篇    下一篇

长江河口悬浮泥沙的混合过程

刘红1,2, 何青1, 王亚1, 陈吉余1   

  1. 1. 华东师范大学河口海岸学国家重点实验室, 上海200062;
    2. 中交上海航道勘察设计研究院有限公司, 上海200120
  • 收稿日期:2012-03-31 修回日期:2012-05-23 出版日期:2012-09-20 发布日期:2012-11-09
  • 通讯作者: 何青,教授,博导。E-mail:qinghe@sklec.ecnu.edu.cn E-mail:qinghe@sklec.ecnu.edu.cn
  • 作者简介:刘红(1978-),男,湖北宜昌人,博士,高级工程师,主要从事河口海岸水动力和工程泥沙研究。E-mail:liuhg007@yahoo.com.cn
  • 基金资助:

    国家自然科学基金项目(41076051); 创新研究群体项目(41021064); 上海市科委重点项目(11dz1204900);河口海岸学国家重点实验室开放基金项目(SKLEC-KF201201)

Processes of Suspended Sediment Mixture in the Yangtze River Estuary

LIU Hong1,2, HE Qing1, WANG Ya1, CHEN Jiyu1   

  1. 1. State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China;
    2. Shanghai Waterway Engineering Design and Consulting Co., Ltd., Shanghai 200120, China
  • Received:2012-03-31 Revised:2012-05-23 Online:2012-09-20 Published:2012-11-09
  • Supported by:

    National Natural Science Foundation of China, No.41076051; Creative Research Groups of China, No. 41021064; Key Project of the Shanghai Science & Technology Committee, No. 11dz1204900; Open Research Fund of State Key Laboratory of Estuarine and Coastal Research, No. SKLEC-KF201201

摘要: 根据准同步观测的悬浮泥沙及表层沉积物粒度、流速、含沙量资料, 分析了长江口及临近海域悬浮泥沙在河口的混合过程。长江河口—陆架系统悬浮泥沙中值粒径呈现“细—粗—细”的变化规律, 河口上段悬浮泥沙中值粒径为8.9 μm, 拦门沙海域为10.5 μm, 陆架区为4.5 μm, 北支为9.9 μm, 杭州湾口为5.6 μm, 泥沙类型为粘土质粉砂。河口上段和陆架区悬浮泥沙与表层沉积物的垂向混合作用较弱, 拦门沙区域二者发生强烈的混合和交换, 悬浮泥沙在由长江河口向陆架系统输移过程中仅有表层泥沙保留了流域输入的泥沙粒度特征。长江口悬浮泥沙中值粒径与含沙量呈良好的正相关关系, 水流的剪切作用是引起拦门沙海域泥沙再悬浮、近底高含沙量和悬浮泥沙粒径增加的主要原因, 悬浮泥沙粒径和含沙量的增加主要由粉砂组分的增加引起。2007 年长江河口区范围内悬浮泥沙中值粒径比2003 年普遍减小11%, 含沙量比2003 年减小22%, 河口上段含沙量对流域来沙减少的响应最为敏感, 而拦门沙区的泥沙粒径对流域来沙减少的响应最敏感。在长江流域来沙量减少的背景下, 河口拦门沙区域仍能维持较高的含沙量, 主要缘于河口系统内部的供沙

关键词: 长江口, 悬浮泥沙, 含沙量, 泥沙混合, 流速梯度

Abstract: Based on the sub-simultaneous data of grain size distributions (GSDs) of suspended and surface sediment, current velocity, suspended sediment concentration (SSC), the mixing processes between suspended and surface sediment were conducted in the Yangtze River Estuary and adjacent area. The characteristics of suspended sediment D50 (SSD) were showed a fine-coarse-fine pattern from the Yangtze River Estuary to continental shelf. The SSD were 8.9 μm, 10.5 μm and 4.5 μm in the upper Yangtze River Estuary, mouth bar area and continental shelf respectively, and were 9.9 μm and 5.6 μm in the North Branch and Hangzhou Bay respectively. Clayey silt was the dominant sediment type in the study area. The vertical mixing processes between suspended and surface sediments were weak in the upper estuary and the continental shelf, while it was strong in the mouth bar area. Only surface layer of suspended sediment retained the characteristics of GSDs from the Yangtze River basin. Good positive correlations were observed between the SSD and SSC, and the sediment resuspension by the shear flow was the main causes of SSC and SSD increase near the bottom. The SSD of the Yangtze Estuary in the year 2007 decreased by 11% compared with 2003, while the SSC decreased by 22% in the same period.

Key words: Yangtze River Estuary, suspended sediment, suspended sediment concentration, sediment mixing, velocity gradient