| 长江河口区上段水、悬沙通量及其对北支演化的意义 |
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| 引用本文： | 闵凤阳, 汪亚平, 杨旸, 高建华, 张志林, 徐海东. 长江河口区上段水、悬沙通量及其对北支演化的意义[J]. 第四纪研究, 2012, 32(6): 1140-1151. doi: 10.3969/j.issn.1001-7410.2012.06.08 |
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| 作者姓名： | 闵凤阳 汪亚平 杨旸 高建华 张志林 徐海东 |
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| 作者单位： | ① 长江科学院河流研究所, 武汉 430010;; ② 南京大学海岸与海岛开发教育部重点实验室, 南京 210093;; ③ 华东师范大学河口海岸学国家重点实验室, 上海 200062;; ④ 长江水利委员会长江口水文水资源勘测局, 上海 200136 |
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| 基金项目： | 江苏省自然科学基金项目，华东师范大学河口海岸学国家重点实验室开放基金项目，国家自然科学基金项目 |
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| 摘 要： | 2007年9月在长江河口3条控制断面的全潮观测结果表明,长江口南支均以落潮流和落潮输沙占优,而北支大、小潮期间的水沙输运特征迥异; 其特征与长江径流、河口地形地貌特征密切相关。小潮期间,长江口北支以落潮流占优; 大潮期间,则以涨潮流占优,且悬沙输运率比小潮期间增大一个数量级。分析结果进一步表明,从1958年至今,长江口北支的分流比呈下降的趋势,已由11.8% 降至目前的1.9%; 长江口北支也由早期的悬沙输入(与径流方向相反)通道变为输出通道,目前其分沙比仍达6.4% ~7.9% 左右。总体上,分流分沙比呈显著减小趋势,这是长江口北支萎缩的重要特征之一。此外,北支分沙比显著大于分流比,将可能造成北支的进一步淤积。
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| 关 键 词： | 水沙通量 分流分沙比 长江口 北支 |
| 收稿时间： | 2012-07-04 |
| 修稿时间： | 2012-09-03 |
THE WATER AND SUSPENDED SEDIMENT FLUXES IN UPPER BRANCHES OF CHANGJIANG ESTUARY AND THEIR IMPLICATION ON CHANNEL EVOLUTION OF NORTH BRANCH |
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| Min Fengyang, Wang Yaping, Yang Yang, Gao Jianhua, Zhang Zhiling, Xu Haidong. THE WATER AND SUSPENDED SEDIMENT FLUXES IN UPPER BRANCHES OF CHANGJIANG ESTUARY AND THEIR IMPLICATION ON CHANNEL EVOLUTION OF NORTH BRANCH[J]. Quaternary Sciences, 2012, 32(6): 1140-1151. doi: 10.3969/j.issn.1001-7410.2012.06.08 |
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| Authors: | Min Fengyang Wang Yaping Yang Yang Gao Jianhua Zhang Zhiling Xu Haidong |
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| Affiliation: | ① River Research Department, Changjiang River Scientific Research Institute, Wuhan 430010;; ② Key Laboratory of Coast and Island Development, Ministry of Education, Nanjing University, Nanjing 210093;; ③ State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062;; ④ The Survey Bureau of the Hydrology and Water Resources of Changjiang Estuary, Changjiang Water Resources Commission, Shanghai 200136 |
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| Abstract: | The North Branch,which is an individual channel of Changjiang estuary entering the sea,has been experienced great siltation since 1950s for the significantly changes in hydrodynamics and channel geomorphology.In Sep.2007,sediment dynamic parameters were surveyed during the neap and spring tides at North Branch,South Branch and Xuliujing cross-section in the upper Changjiang estuary.The hydrodynamic characteristics are observed by ADCP at North Branch、South Branch and ADP for the Xuliujing cross-section.The acoustic signals recorded have a significant relationship with the suspended sediment concentrations(SSCs)obtained by in-situ water sampling during the measurements,then the acoustic SSC models established were used to convert ADCP(ADP)acoustic signals into high-resolution SSCs along the cross-sections at North Branch,South Branch and Xuliujing.Thus,the water and suspended sediment fluxes could be estimated.The results show that in South Branch,the current velocity and sediment flux were larger during the ebb than those during the flood both in the neap and spring tides.Comparison with the South Branch,the hydrodynamic and sediment transport characteristic of North Branch were of great difference.During the neap tide,the current velocity was larger during the ebb than that during the flood; on the contrary,during the spring tide,the maximum current velocity was smaller during the ebb than that during flood,and the net suspended sediment fluxes was more than 10 times during the flood period than that the ebb.These features were consistent with the water and sediment discharge division ratio variations in North Branch.The water discharge division ratio decreases from 11.8% to 1.9% during 1958~2007,and the suspend sediment discharge division ratio is about 6.4% ~7.9% at present.Thus,the higher sediment discharge division ratio than the water division ratio could result in the further siltation in North Branch.In addition,the North Branch acted as the importing channel in terms of the suspended sediment(transport landward)in the early stage; however,it changed into the outputting channel at present.As a whole,the water and sediment discharge ratio decreased significantly since 1950s,which is an important characteristics for the North Branch degeneration. |
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| Keywords: | water and suspend sediment flux division ratio of water and sediment discharge Changjiang estuary North Branch |
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