长江口北支上段滩槽演变过程研究  

Study on Evolutionary Process of Shoal-Channel at Upper Reach of the North Branch of the Changjiang Estuary

作　　者：王凌霄 戴志军[1] 梅雪菲 王杰[1] 楼亚颖 乔红杰 WANG Lingxiao;DAI Zhijun;MEI Xuefei;WANG Jie;LOU Yaying;QIAO Hongjie(State Key Laboratory of Estuarine and Coastal Research,Shanghai 200241,China;Yangtze River Estuary Survey Bureau of Hydrology and Water Resources,Changjiang Water Resources Commission,Shanghai 200136,China)

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200241 [2]长江水利委员会水文局长江口水文水资源勘测局,上海200136

出　　处：《海洋科学进展》2024年第4期663-676,共14页Advances in Marine Science

基　　金：国家自然科学基金联合基金项目(U2040202);国家自然科学基金面上项目(42076174);国家重大社科基金项目(23&ZD105);上海市国际科技合作基金项目(20230713800)。

摘　　要：滩槽系统是河口普遍存在的地貌单元,其演变过程直接关乎航槽稳定与滩涂资源利用。利用1992年—2022年长江口北支上段实测地形资料、Landsat遥感影像及长江入海水沙、南北支分流比等数据,分析北支上段滩槽演变过程及可能的影响因素。结果表明,崇头边滩淤涨速率为0.32 km^(2)/a,新跃沙为0.25 km^(2)/a,其中超过50%的研究区边滩淤涨发生在2000年—2003年。同时,崇头河槽在2000年—2008年发生明显侵蚀,容积扩大超过50%。崇头边滩与新跃沙淤涨泥沙来源主要由潮流带入,受上游来沙影响较小。由于北支青龙港河道弯曲及涌潮现象,引起新跃沙快速淤涨。崇头边滩在洪季受径潮流顶托造成泥沙落淤;在枯季因科氏力与淤涨滩涂扩展,形成涨潮冲刷槽,构成北支“槽冲滩淤”的特点。Shoal-channel system is a common estuarine geomorphic unit.Its evolution process directly dominates the channel stability and tidal flat utilization.Based on historical bathymetric charts,Landsat remote sensing images,fluvial water and sediment discharge records and the discharge diversion ratios,this study explored the shoal-channel evolution process of upper reach of the North Branch during 1992-2022.The results showed that Chongtou Shoal and Xinyue Shoal exhibit an average annual siltation of 0.32 km^(2) and 0.25 km^(2),respectively,with over 50%of siltation occurring during 2000-2003.The channel of the Chongtou Shoal experienced significant erosion during 2000-2008,with the volume enlarging by exceeding 50%;while the channel of the Xinyue Shoal changed relatively small.Landward sediment transport from the sea to the North Branch driven by tidal current supports siltation of the Chongtou and Xinyue Shoals,while fluvial sediment supply has a slight contribution;The curved channel pattern around the Qinglong Port and tidal surge are responsible for the Xinyue Shoal siltation,During the flood season,the ebb and flow of tidal currents are responsible for the Chongtou Shoal siltation.Due to Coriolis force and shoal expansion,flood current flows to the north and generates flood channel in dry season,and thus the North Branch s is featured by"channel erosion and shoal siltation".

关 键 词：滩槽系统 动力地貌演变 潮汐不对称 长江口 北支 

分 类 号：P737.1[天文地球—海洋地质]