王凌霄, 戴志军, 梅雪菲, 等, xxxx. 长江口北支上段滩槽演变过程研究[J]. 海洋科学进展, x(x): xx-xx. doi: 10.12362/j.issn.1671-6647.20230825001.
引用本文: 王凌霄, 戴志军, 梅雪菲, 等, xxxx. 长江口北支上段滩槽演变过程研究[J]. 海洋科学进展, x(x): xx-xx. doi: 10.12362/j.issn.1671-6647.20230825001.
WANG L X, DAI Z J, MEI X F, et al, xxxx. Study on evolutionary process of shoal-channel at upper reach of north branch of the changjiang estuary[J]. Advances in Marine Science, x(x): xx-xx. DOI: 10.12362/j.issn.1671-6647.20230825001
Citation: WANG L X, DAI Z J, MEI X F, et al, xxxx. Study on evolutionary process of shoal-channel at upper reach of north branch of the changjiang estuary[J]. Advances in Marine Science, x(x): xx-xx. DOI: 10.12362/j.issn.1671-6647.20230825001

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 North Branch of the Changjiang Estuary

  • 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。本文利用1992—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 km2/a,新跃沙为0.25 km2/a,其中超过50%的研究区边滩淤涨发生在2000—2003年。同时,崇头河槽在2000—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。

     

    Abstract: 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 chart, Landsat remote sensing images, fluvial water and sediment discharge records and the discharge diversion ratio, the shoal-channel evolution process of upper reach of the North Branch during 1992—2022 is explored. The results show that Chongtou Shoal and Xinyue Shoal exhibit an average annual siltation of 0.32 km2 and 0.25 km2, respectively, with over 50% of siltation occurring between 2000-2003. The channel of Chongtou Shoal experienced significant erosion during 2000—2008, with the volume enlarging by over 50%; while the channel of Xinyue Shoal changed relatively small. Landward sediment transport from the sea to the North Branch driven by tidal current supports siltation of Chongtou Shoal and Xinyue Shoal, while fluvial sediment supply has a slight contribution; The curved channel pattern around 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, and due to Coriolis force and shoal expansion, flood current flows to the north and generates flood channel in dry season, North Branch thus is featured by "channel erosion and shoal siltation" .

     

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