应用遥感方法分析珠江口伶仃洋的海岸线变迁及其环境效应

Application of the remote sensing method in the analysis of the shoreline change and its environmental impact in the Lingdingyang Bay,Pearl River estuary,Guangdong,China

对伶仃洋1979年以来利用多时相遥感影像提取的岸线进行分析,结合地形图,得到近几十年来海岸线变化的特征,认为南沙区和蛇口半岛是岸线变化最快的2个区,而淇澳岛区和交椅湾区的变化相对较小。南沙区岸线变迁以沉积作用和围海造地形成的岸线向海延伸为主,延伸速率从1966年至2000年明显增大,2000年后有减缓的趋势。蛇口半岛区主要以码头、池塘等人工建筑形成的岸线向海延伸为主。从岸线变迁、悬浮沉积物分布及其沉积作用来看,伶仃水道西侧以沉积为主,可能不适合于大规模的码头建设。珠江口岸线变迁最主要的环境效应是河道变窄、增长,造成排洪不畅,上游的洪涝灾害增多。

The features of shoreline changes over the past few decades were obtained through analyses of the shorelines of the Lingdingyang Bay, Pearl River estuary, Guangdong, extracted from multi-temporal satellite images since 1979 and topographic maps. It may be concluded that the most rapid changes occur on the Nansha district and the Shekon peninsula, while the changes in the Qi＇ao district and Jiaoyi Bay are relatively small. The changes in the Nansha district are mainly marked by seaward extension of the shoreline resulting from sedimentation and reclamation of land from the sea and the extension rate increased markedly from 1966 to 2000 and had a trend of decrease after 2000. The seaward extension of the shoreline on the Shekou Peninsula was due to the construction of the harbor and dyke-pond system. The shoreline change and suspended sediment plume distribution and sedimentation show that sedimentation predominates to the west of the Lingding waterway of the estuary. Therefore, this site is probably not suited for large-scale harbor construction. The most important impacts of the shoreline changes in the Pearl River estuary are narrowing and extension of the river channel, which results in difficult discharge of floods and an increase in flooding and waterlogging in the upper reaches of the river.