长江口北支悬沙浓度及输移的时空变化  

Temporal and spatial variations in suspended sediment concentration and transport in the North Branch of the Yangtze Estuary

作　　者：张二凤[1] 陈沈良[1] 谷国传[1] 杨海飞[1] 王如生[1] 

机构地区：[1]华东师范大学河口海岸学国家重点实验室,上海200062

出　　处：《海洋学报》2015年第9期138-151,共14页

基　　金：科技部河口海岸学国家重点实验室科研业务课题(SKLEC-2012KYYW06);科技部科技基础性工作专项重点项目(2013FY112000)

摘　　要：本文基于4次洪枯季同步水文观测资料,着重分析了长江口北支悬沙浓度的潮周期变化、垂向分布、纵向分布和悬沙输移及其时空差异。研究结果显示,悬沙浓度的潮周期变化过程在大中潮期以M型(双峰型)为主,下段主槽内在大潮期多出现V型,上段在枯季可出现涨潮单峰型;小潮期可出现无峰、单峰或双峰型。涨、落潮悬沙浓度峰值及均值,在枯季多涨潮大于落潮,洪季中小潮特别是小潮期易出现落潮大于涨潮;下段主槽内在大潮期易出现落潮大于涨潮。悬沙浓度的垂向分布及其变化特点,在大中潮期与悬沙的潮周期变化型式有关,其中M型存在显著的洪枯季差异。纵向上,最高悬沙浓度在枯季出现于中段灵甸港至三和港之间及附近河段,洪季则在下段三条港附近。潮周期悬沙净输移,枯季大多向陆特别是大中潮期,洪季中上段大多向海,下段大潮期多向陆、中小潮易出现向海;下段主槽内在大潮期易出现向海。Based on 4 synchronous hydrological measurements in flood and dry seasons, this paper researches the variations in suspended sediment concentration （SSC） in a tidal cycle,the vertical distribution of SSC, the longitudi- nal distribution of SSC, the suspended sediment transport,and their temporal and spatial differences in the North Branch of the Yangtze Estuary. The results indicate that the process of variations in SSC in a tidal cycle mainly presents M pattern （two peaks） during spring and medium tides. However,in the main channel of the lower reach mostly V pattern occurs during spring tide,and in the upper reach one-peak during flood pattern could occur in dry season. During neap tide, no-peak, one-peak, or two-peak patterns could occur. About the maximum and average SSC during flood and ebb, they are usually larger during flood in dry season,in flood season more likely larger dur- ing ebb in medium and neap tides particularly in neap tide. In the main channel of the lower reach they are more likely larger during ebb in spring tide. The vertical distribution of SSC and its variations in a tidal cycle are related to the variational pattern of SSC during spring and medium tides. For M-pattern SSC it has obvious difference be- tween flood season and dry season. Longitudinally, the maximum SSC occurs nearby the reach between Lingdi- angang and Sanhegang in the middle reach during dry season,however around Santiaogang in the lower reach dur- ing flood season. Regarding the net suspended sediment transport in a tidal cycle,it is usually landward in dry sea- son particularly during spring and medium tides, in flood season mostly seaward in the middle and upper reaches, mostly landward during spring tide and likely seaward during medium and neap tides in the lower reach. In the main channel of the lower reach it is likely seaward during spring tide.

关 键 词：悬沙浓度 悬沙输移 时空变化 长江口北支 

分 类 号：P737.14[天文地球—海洋地质]