1990年以来中国大陆海岸线稳定性研究

海岸线变迁是一个动态的演变过程,它是自然与人类共同作用的结果。基于1990年、2000年、2007年和2012年4个时期的资源卫星、Landsat系列卫星的遥感影像,采用色差Canny算子计算方法提取岸线数据,计算近22 a来中国大陆海岸线向海推进或向陆后退的空间位置变化量及年均变化速度,研究中国大陆海岸线空间位置与稳定性的演变规律,得出以下结论：① 中国海岸线空间位置变化以向海推进为主;② 中国海岸线多为相对稳定海岸线,其次为强烈岸进岸线,稳定性岸线全国均有分布,而强烈岸进岸线多分布于江苏和辽宁两省;③ 自1990年以来,中国大陆岸线的稳定性指数逐渐降低,22 a下降了1.1,以长江入海口为分界,南方沿海城市岸线稳定性指数高于北方。

Stability of Continental Coastline in China Since 1990

Coastline is not only identified the coastal shoreline land and water boundaries but also contains a wealth of environmental information. Coastline change is a dynamic process of evolution, whose changes directly affected intertidal mudflat resources and coastal environment, also cloud cause a variety of changes in the coastal zone resources and ecological processes. These changes can impact on coastal human survival and development.In this study,referencing the economy, marine legal system and the development process of management of sea areas of the ocean, Remote sensing images from Landsat and HJ satellite, of which 12 images from Landsat TM in 1990 and 2007, Landsat ETM+ in 2000 and HJ-1A HJ in 2012 were chosen. Color Canny operator automatic extraction technology was used to extract four periods of continental coastline, then the average Depth degree’s calculating model was built to get the AveD- AveD+ and SY of continental coastline in China. Then the rules of spatial variation characteristics and the stability were obtained nearly 22 years. 1) The promoting seaward distance is the major the variation of spatial distances of continental coastline in China; 2) The stable and strongly forward coastline are the major components of continental coastline in China, and thestable coastline is all over coastal provinces ,then the strongly recessing distributed mainly in the Jiangsu and Liaoning provinces. 3) Over the past 22 years, the stability of continental coastline were declining and its index fell by 1.1. The stability indexes of continental coastline the dividing line is in the Changjiang River estuary, southern coastline are generally higher than the northern coastal cities. It's found that the reason of the changes of shoreline position is the interaction of natural factors and human factors. Their affection are not the same.Natural factors are the main factors affecting the landward retreat of the coastline, such as seawater erosion, sea level rise and land subsidence. Storm surges and other marine disasters also caused shoreline landward retreat. Human use of the sea is a major factor in advancing to the sea coast.Reclamation farming, port construction, land filling, accelerated shoreline seaward. In addition to the extreme marine disasters, the impact of natural factors is mostly continuous and slow, but impact of human activities is quick and direct.