北部湾大风江河口沙嘴动态变化过程  

Dynamic variation of sand spit in the Dafeng River estuary,Beibu Gulf

作　　者：陈益 戴志军[1] 庞文鸿 梁喜幸 罗杰骏 熊媛 CHEN Yi;DAI Zhijun;PANG Wenhong;LIANG Xixing;LUO Jiejun;XIONG Yuan(State Key Laboratory of Estuarine and Coastal Research,East China Normal University,Shanghai 200241,China;Guangxi Key Laboratory of Marine Environmental Change and Disaster in Beibu Gulf,Qingzhou 535011,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]广西北部湾海洋环境变化与灾害研究重点实验室,钦州535011

出　　处：《海洋地质与第四纪地质》2025年第2期43-54,共12页Marine Geology & Quaternary Geology

基　　金：国家自然科学重点基金“北部湾红树林潮滩响应陆海水沙变化的沉积动力过程”(41930537)。

摘　　要：沙嘴的快速变化过程直接关联河口地貌变迁,影响陆海交汇带水沙交换,因而沙嘴地貌的移动及驱动机制成为河口研究重点关注的内容之一。然而,受限于监测资料获取的困难,一直有较少工作涉及中—强潮河口沙嘴动力地貌演变。以北部湾大风江河口沙嘴为研究对象,基于1990—2021年卫星遥感影像、2022年11月实地采集的沙嘴表层沉积物以及区域水文资料,分析中—强潮环境的大风江河口沙嘴演变特征及变化过程。结果表明:(1)大风江河口沙嘴持续向西北延伸,其中沙嘴宽度与面积呈洪季变大、枯季变小的季相变化特征;(2)沙嘴沉积物主要来源为洪季的径流来沙,沙嘴海侧顶部沉积物平均粒径最粗,并向陆侧与中部、尾部逐渐变细。沉积物主要由海侧顶部向沙嘴中部及尾部方向输移,使沙嘴持续向西北延伸。(3)波浪是控制大风江沙嘴长期形态演变的主要因素,中—强潮环境下潮流作用是沉积物向岸输送、沙嘴持续向西北延伸的原因,径流量的洪枯季显著差异是沙嘴宽度与面积洪季变大、枯季变小的主控因素。The rapid change process of sand spit is directly related to the estuarine geomorphological migration with potential impacts on water and sediment exchange between land and sea.The movement and the driving mechanism of sand spit landform have received especial concerns.However,limited information is related to sand spit morphodynamics due to difficulties in obtaining monitoring data.Based on multi-satellite remote sensing images from 1990 to 2023,surface sediments collected in November 2022,and regional hydrological data,the evolution of the sand spit in Dafeng River estuary in Beibu Gulf,Guangxi,SW China over a medium-strong tidal environment were analyzed.Results show that①the sand spit in the estuary exhibited continuous extension to the northwest,and the width and area of the spit featured seasonal variation with increased width in flood season and decreases in dry season;②The main sediment source of the sand spit was from riverine material in flood season.The average grain size of sediments on top the spit seaside was the coarsest and then gradually became finer from sea to land,and to the middle and tail parts of the spit.The sediments were transported mainly from the top of the sediments seaside towards the middle and tail of the spit,so that the spit continued to extend northwestward;③Runoff from sand is the source of sediment in the spit,waves are the main factor controlling the long-term morphological evolution of the sand spit in the estuary.Tidal actions in mild-strong tidal environment are the driver to the sediment transport shoreward and the continuous northwestward extension of the sand spit.The significant difference in seasonal runoff was the main factor on the variations in width and area of the sand spit:greater in flood season and smaller in dry season.

关 键 词：沉积物 遥感影像 河口沙嘴 大风江河口 北部湾 

分 类 号：P736[天文地球—海洋地质]