基于多源遥感影像的宁远河口海岸线变迁分析

Analysis of Ningyuan Estuary coastline transition based on the multi-resource remote sensing image

利用1987年、2000年、2010年和2015年4个时相的多源遥感影像(TM,ETM+,Rapid EYE和Quick Bird),基于面向对象的信息提取技术,采用密度分割法和二值化合并处理,开展了宁远河口1987—2015年间4个阶段海岸线信息提取,并分析了海岸线时空变化特征、海岸线变迁的影响因素和发展趋势。研究表明,1987—2015年间,宁远河口海岸线长度总体呈增加趋势,海岸线总长度增加了约8. 14 km;宁远河口海岸带生态环境发生了较大变化,河口内河道红树林资源基本消失,人工养殖区规模逐年扩大,河流入海口水体水质逐年下降;河口三角洲区域海岸线总体上表现为淤积,河口以西区域表现为侵蚀;海岸线变迁的主要影响因素包括海岸侵蚀淤积、滩涂围垦养殖、人工岛屿及防沙堤坝建设等;宁远河口的侵淤形势不容乐观,其发展趋势表现为人工岛屿西侧海岸线将进一步被侵蚀,而防沙堤坝东侧的淤积将进一步加剧。

In this paper,by utilizing4phases of multi-resource remote sensing images in1987,2000,2010and2015,the authors carried out the information extraction of coastline in Ningyuan Estuary in4phases from1987to2015,and analyzed spatial and temporal characteristics,influencing factors and development trend of coastline transition by using the density segmentation and binarization processing based on object-oriented information extraction technology.Some conclusions have been reached:The coastline of Ningyuan Estuary overall showed a trend of growth from1987to2015,with the total length increasing up to8.14km.The ecological environment of the coastal zone in Ningyuan Estuary has changed greatly with the disappearance of mangrove resources near the estuary largely,the expansion of artificial breeding zones and the continuous deterioration of water quality.The overall feature in the delta of Ningyuan Estuary is siltation,and that in the west of the estuary is erosion.The major influencing factors include coastal erosion and siltation,artificial breeding in the tideland and the construction of the artificial island as well as the building of a dam for sand control.The situation of Ningyuan Estuary is not optimistic in recent years.The erosion of the artificial island's west coastline tends to become worse and the coastal siltation will be further intensified in the east of the sand-protecting dam.