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基于LiDAR观测的长江河口南汇南滩近期动力地貌研究
引用本文:王杰,戴志军,魏稳,葛振鹏,庞文鸿,马彬彬,梅雪菲,于亚文. 基于LiDAR观测的长江河口南汇南滩近期动力地貌研究[J]. 海洋与湖沼, 2018, 49(4): 756-768
作者姓名:王杰  戴志军  魏稳  葛振鹏  庞文鸿  马彬彬  梅雪菲  于亚文
作者单位:华东师范大学河口海岸学国家重点实验室
基金项目:国家重点研发计划项目,2017YFC0506002号;国家自然科学基金项目,41706093号,41576087号。
摘    要:南汇潮滩是长江河口重要的后备国土资源,其地貌的动态变化过程可敏锐反映河海相互作用的强弱。本文利用地面LiDAR获取了南汇南滩2016年4月—2017年5月逐月大潮低潮期间滩面地貌高分辨率点云数据,根据平均小潮高、低潮位将潮滩划分为上、中和下部,由此结合水文泥沙资料分析区域潮滩动力地貌演变过程。结果表明:(1)潮滩在观测期间整体向海淤涨,其一年间垂向淤积值为10 cm,其中潮滩中部面积增大,而潮滩上部和下部的面积均减小;(2)滩面变化具有明显的夏秋季弱侵蚀调整、冬春季强淤积推进的季节性特征,潮滩地貌侵蚀-淤积则呈现明显的空间分异。在潮滩上部中侧-中部西侧形成贯通的冲刷带(10—80cm),上部沿堤西侧植被区出现强淤积带(20—85cm),整个滩面中东部潮滩出现大面积的弱淤积(5—30cm);(3)南汇南滩并未因长江入海泥沙的剧烈减少而遭受侵蚀,这可能受控于局地基本未变的动力环境和悬浮泥沙浓度,冲刷-淤积的纵向分带性则与区域海堤导致的潮流流向发生改变有关。

关 键 词:地面LiDAR技术  动力地貌  南汇南滩  长江河口
收稿时间:2017-11-11
修稿时间:2017-12-29

LIDAR-BASED RECENT MORPHODYNAMIC STUDY OF SOUTH NANHUI TIDAL FLAT, CHANGJIANG ESTUARY
WANG Jie,DAI Zhi-Jun,WEI Wen,GE Zhen-Peng,PANG Wen-Hong,MA Bin-Bin,MEI Xue-Fei and YU Ya-Wen. LIDAR-BASED RECENT MORPHODYNAMIC STUDY OF SOUTH NANHUI TIDAL FLAT, CHANGJIANG ESTUARY[J]. Oceanologia Et Limnologia Sinica, 2018, 49(4): 756-768
Authors:WANG Jie  DAI Zhi-Jun  WEI Wen  GE Zhen-Peng  PANG Wen-Hong  MA Bin-Bin  MEI Xue-Fei  YU Ya-Wen
Affiliation:State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China,State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China,State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China,State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China,State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China,State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China,State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China and State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
Abstract:The Nanhui tidal flat is an important reserve of land resources in the Changjiang (Yangtze) River estuary, in which the morphodynamic processes reflect directly the relative strength between the river and sea forces. Based on high-resolution monthly point cloud data in spring tide period from April 2016 to May 2017 and the associated hydrological and sediment records, we studied the geomorphological evolution of the tidal flat. The tidal flat could be divided into three zones, namely, upper, middle, and lower zone in terms of the mean high and low water levels of neap tide. The main results are followed. (1) The Nanhui tidal flat stretches seaward overall during the observation period with a vertical deposition rate of 10cm. The land area of the middle flat zone increased while those of the upper and lower flat zones decreased in trend. (2) The geomorphological evolution of the flat varied seasonally with weak erosion in summer and autumn, and strong deposition in winter and spring. Meanwhile, apparent spatial differences were detected along the tidal flat. A scouring zone in the depth between 10 cm and 80 cm runs through the middle of the upper flat zone and the west side of the middle flat zone. A strong silt range (20-85cm) occurred along the vegetation area of the upper zone. In addition, a large scale of weak siltation (5-30cm) appeared in the middle-eastern part of the tidal flat. (3) The Nanhui tidal flat did not suffer erosion with the large decrease of riverine sediment, indicating that its morphodynamic processes were affected mainly by the local hydrodynamic condition and suspended sediment concentration. Moreover, the longitudinal zoning of erosion-deposition could be explained by the regional seawall-induced variation of flow direction.
Keywords:terrestrial LiDAR technology  morphodynamics  South Nanhui tidal flat  the Changjiang River Estuary
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