摘要
通过对比分析1996-2013年的实测水沙资料,研究了长江口最大浑浊带悬沙粒度对流域减沙的响应。流域减沙后浑浊带悬沙粒度细化,全潮垂线平均中值粒径洪季下降20%,其中小潮下降10%~30%,大潮下降10%左右;枯季基本持平,其中小潮下降20%~50%,但大潮增加20%~90%。悬沙粒度垂向差异增加,表底层粒径差洪季由1.01μm增加至2.30μm;枯季由-0.60μm增加至5.62μm。潮动力对悬沙粒度的影响更显著,减沙前洪枯季大小潮粒径差均小于1μm,减沙后分别增加至1.97μm与7.08μm。减沙后最大浑浊带与南港的悬沙粒径差异变大,由14.4%增加至29.0%;但与口外海域之间差异维持在9%左右。流域减沙后,浑浊带悬沙粒度更接近口外,海域来沙对最大浑浊带悬沙粒度的影响增加,最大浑浊带泥沙来源发生变化,口外供沙特性初现。
Based on the observed data of the Yangtze Estuary turbidity maximum zone in 1996,1997,2011 and 2013,the response of the grain size to sediment reduction is studied.After the sediment reduction,the grain size of the Yangtze Estuary turbidity maximum zone witnessed a refining variation progress.The vertical average median particle diameter of flood season decrease about 20%,decrease 10%-30%during the flood season neap tide and decrease about 10%during the flood season spring tide.The vertical average median particle diameter of the dry season nearly remains,decrease 20%-50%during the dry season neap tide,but increase 20%-90%in the dry season spring tide.The variety of the grain size along depth increase,grain size difference from the surface to bottom increase from 1.01μm to 2.30μm in the flood season,and from-0.60μm to 5.62μm in the dry season.Impact of tidal power on the grain size become more obvious,the difference between the spring tide and the neap tide before the sediment reduction is less than 1μm,but change to 1.97μm and 7.08μm in the flood and dry season after the sediment reduction respectively.The grain size difference between the turbidity maximum zone and Nangang at upstream increase from 14.4%to 29.0%,but the grain size difference between the turbidity maximum zone and the outside of the estuary at downstream remains the same,stay around 9%.It is suggested that after the sediment reduction,the grain size of the Yangtze Estuary turbidity maximum zone gets closer to the water outside the mouth.Sediment from outside of the mouth have more influence on the turbidity maximum zone,and the sediment source of the turbidity maximum zone begin to change.
作者
于上
何青
陈语
邓智瑞
YU Shang;HE Qing;CHEN Yu;DENG Zhi-rui(State Key Laboratory of Estuarine and Coastal Research,East China Normal University,Shanghai 200241,China)
出处
《泥沙研究》
CAS
CSCD
北大核心
2021年第4期60-67,共8页
Journal of Sediment Research
基金
国家自然科学基金项目(51739005)
国家重点研发计划项目(2016YFE133700)
上海市科委重大研究项目(17DZ1204801)
上海市科委重大研究项目(18DZ1206400)。
关键词
长江口
最大浑浊带
悬沙粒度
减沙
Yangtze Estuary
turbidity maximum zone
grain size
sediment reduction
