1988-2021年珠江口内伶仃洋滩涂结构遥感监测研究

A monitoring study on tidal-flat structures in the Inner Lingding Sea for Pearl River Estuary during 1988-2021

【目的】为揭示沿海城市周期性潮位影响下滩涂范围与地貌结构,【方法】基于GEE平台搜集Landsat影像数据,通过潮位影像融合算法构建珠江口内伶仃洋1988—2021年逐3 a海岸带滩涂结构数据集,辨析滩涂结构时空演变过程及其与海岸带工程的关系。【结果】结果显示,截至2021年,内伶仃洋(含深圳湾北部)共有滩涂33.7 km^(2),主要分布于深圳湾北部、龙穴岛、蕉门至横门海岸带,深圳段占比42%,中山段占比25%,广州段和东莞段面积狭小。内伶仃洋滩涂整体呈现出波动下降趋势,且出现频率逐渐降低,12期滩涂总面积累计减少65.39 km^(2),潮上带从15.67 km^(2)减少至4.25 km^(2),潮间带37.32 km^(2)减少至5.44 km^(2),潮下带则46.14 km^(2)减少至24.04 km^(2),整体上滩涂潮间带和潮上带缩减面积最大。【结论】长序列影像序列可有效识别潮上带和潮间带的动态转化,填海造陆工程扩张导致整体滩涂的永久性占用,而生态修复工程则有效维持了部分滩涂的面积和分布范围。

[Objective]To reveal the extent and geomorphologic structure of the tidal-flat under the influence of cyclic tide level in coastal cities,[Methods]based on the GEE platform,we collected Landsat image data,and constructed a 3 a tidal-flat structure dataset of the Inner Lingding Sea in the Pearl River Estuary from 1988 to 2021 by means of the tidal imagery fusion algorithm to analyze the structure of the beach and its spatio-temporal evolutions in conjunction with the Coastal Zone Project.[Results]The result showed that,a total of 33.7 km^(2)of tidal-flat were found in Inner Lingding Sea(including the northern part of Shenzhen Bay),mainly distributed in the northern part of Shenzhen Bay,Longdan Island,and the coastal zone from Jiaomen to Hengmen,with the proportion of the Shenzhen section accounting for 42%,that of the Zhongshan section accounting for 25%,and that of the Guangzhou section and the Dongguan section being narrow in area.Inner Lingding Sea tidal-flat as a whole showed a flucting downward trend of tidal-flat,and the frequency of occurrence gradually reduced,12 period of the total area of tidal-flat cumulative reduction of 65.39 km^(2),the supratidal zone from 15.67 km^(2)reduced to 4.25 km^(2),the intertidal zone of 37.32 km^(2)reduced to 5.44 km^(2),the subtidal zone of 46.14 km^(2)reduced to 24.04 km^(2),the overall intertidal zone of the mudflats and the supratidal zone Overall,the intertidal and supratidal zones of the mudflat had the largest reduction in area.[Conclusion]The dynamic transitions of the supratidal and intertidal zones can be effectively recognized by long time-series images.The expansion of reclamation projects has result ed in the permanent occupation of the whole tidal-flat,while the ecological restoration projects have effectively maintained the area and distribution of partial tidal-flat.