| 长江口北支悬沙浓度在潮周期内和大小潮周期尺度的变化特征及输运研究 |
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| 作者姓名： | LI Zhanhai LI Michael Z DAI Zhijun ZHAO Fangfang LI Jiufa |
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| 作者单位： | State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China,Geological Survey of Canada (Atlantic), Bedford Institute of Oceanography, dartmouth, B2Y 4A2, Canada,State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China,State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China,State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China |
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| 基金项目： | The National Science Foundation of China under contract Nos 50939003 and 41176069; the Foundation of State Key Laboratory of Estuarine and Coastal Research, East China Normal University of China under contract No. SKLEC-2012KYYW06. |
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| 摘 要： | Profiles of tidal current and suspended sediment concentration(SSC) were measured in the North Branch of the Changjiang Estuary from neap tide to spring tide in April 2010. The measurement data were analyzed to determine the characteristics of intratidal and neap-spring variations of SSC and suspended sediment transport. Modulated by tidal range and current speed, the tidal mean SSC increased from 0.5 kg/m3 in neap tide to 3.5 kg/m3 in spring tide. The intratidal variation of the depth-mean SSC can be summarized into three types: V-shape variation in neap tide, M-shape and mixed M-V shape variation in medium and spring tides. The occurrence of these variation types is controlled by the relative intensity and interaction of resuspension, settling and impact of water exchange from the rise and fall of tide. In neap tide the V-shape variation is mainly due to the dominant effect of the water exchange from the rise and fall of tide. During medium and spring tides, resuspension and settling processes become dominant. The interactions of these processes, together with the sustained high ebb current and shorter duration of low-tide slack, are responsible for the M-shape and M-V shape SSC variation. Weakly consolidated mud and high current speed cause significant resuspension and remarkable flood and ebb SSC peaks. Settling occurs at the slack water periods to cause SSC troughs and formation of a thin fluff layer on the bed. Fluxes of water and suspended sediment averaged over the neap-spring cycle are all seawards, but the magnitude and direction of tidal net sediment flux is highly variable.
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| 关 键 词： | suspended sediment concentration intratidal and neap-spring variation impact of water exchange resuspension settling Changjiang(Yangtze River) Estuary |
| 收稿时间： | 2013/11/18 0:00:00 |
| 修稿时间： | 6/4/2014 12:00:00 AM |
Intratidal and neap-spring variations of suspended sediment concentrations and sediment transport processes in the North Branch of the Changjiang Estuary |
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| LI Zhanhai,LI Michael Z,DAI Zhijun,ZHAO Fangfang,LI Jiufa.Intratidal and neap-spring variations of suspended sediment concentrations and sediment transport processes in the North Branch of the Changjiang Estuary[J].Acta Oceanologica Sinica,2015,34(1):137-147. |
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| Authors: | LI Zhanhai LI Michael Z DAI Zhijun ZHAO Fangfang and LI Jiufa |
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| Institution: | 1.State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China2.Geological Survey of Canada (Atlantic), Bedford Institute of Oceanography, dartmouth, B2Y 4A2, Canada |
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| Abstract: | Profiles of tidal current and suspended sediment concentration (SSC) were measured in the North Branch of the Changjiang Estuary from neap tide to spring tide in April 2010. The measurement data were analyzed to determine the characteristics of intratidal and neap-spring variations of SSC and suspended sediment transport. Modulated by tidal range and current speed, the tidal mean SSC increased from 0.5 kg/m3 in neap tide to 3.5 kg/m3 in spring tide. The intratidal variation of the depth-mean SSC can be summarized into three types: V-shape variation in neap tide, M-shape and mixed M-V shape variation in medium and spring tides. The occurrence of these variation types is controlled by the relative intensity and interaction of resuspension, settling and impact of water exchange from the rise and fall of tide. In neap tide the V-shape variation is mainly due to the dominant effect of the water exchange from the rise and fall of tide. during medium and spring tides, resuspension and settling processes become dominant. The interactions of these processes, together with the sustained high ebb current and shorter duration of low-tide slack, are responsible for the M-shape and M-V shape SSC variation. Weakly consolidated mud and high current speed cause significant resuspension and remarkable flood and ebb SSC peaks. Settling occurs at the slack water periods to cause SSC troughs and formation of a thin fluff layer on the bed. Fluxes of water and suspended sediment averaged over the neap-spring cycle are all seawards, but the magnitude and direction of tidal net sediment flux is highly variable. |
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| Keywords: | suspended sediment concentration intratidal and neap-spring variation impact of water exchange resuspension settling Changjiang (Yangtze River) Estuary |
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