1987—2017年海南岛海岸线变化特征遥感分析

Remote Sensing Analysis of Coastline Changes in Hainan Island during 1987-2017

利用海岸线、红树林和近海围塘养殖等多个遥感专题信息产品,从岸线年均变化速率、利用率和综合利用程度等方面综合分析了海南岛1987—2017年的海岸线变化特征,并通过典型岸线类型变化探讨了人类活动对海南岛海岸带资源的影响。分析发现:1)海岸线长度总体呈稳定增长趋势。由1987年的1 655 km增至2017年的1 890 km,其中自然岸线持续减少,人工岸线急剧增长。2)岸线类型多样性降低,倾向性明显;而岸线的利用程度不断提高,利用程度综合指数由1987年的237.34增加到2017年的285.03,人类活动对海岸线变迁的干扰作用越来越明显。3)陆海格局变化特征复杂,整体呈向海扩张的态势。多种人为因素共同作用是导致岸线不断变迁的主要原因,人工养殖塘的开发使红树林湿地遭到侵占,生物岸线减少,港口建设、近海人工岛建设等引起砂质岸线等自然岸线减少。

Coastal zone of Hainan is one of the most valuable areas of natural resources and also forms a good ecological environment.Based on a 30-years coastal data derived from satellite imagery,which includes coastline,mangrove,nearshore aquaculture ponds,artificial islands,and ports,this study analyzed the coastline changes and other spatial elements in the coastal zone of Hainan Island.The human activities that impacted on the coasts of Hainan were also evaluated.The indices used for the analysis were:Length Change Intensity(LCI),Index of Coastline Type Diversity(ICTD),and Index of Coastline Utilization Degree(ICUD).In this study,we found that:1)the length of the coastline increased steadily from 1,655 km(in 1987)to 1,890 km(in 2017).In contrast,the natural coastline length decreased continuously from 1,565 km(in late 1980s)to 1,140 km(in 2017),with a proportion drop from 94.6%to 60.3%.The length and proportion of artificial shoreline increased remarkably,from 90 km(in late 1980s)up to 750 km(in 2017)and a proportion changed from 5.40%to 39.7%.2)The diversity of coastline types decreased while the coastline utilization degree increased.From 1987 to 2017,the ICUD increased continuously from 237.34 to 285.03,indicating that human activities had an increasing effect on coastline changes.3)Land and sea pattern changes were complicated,with the coastline expanding into the sea.Overall,the coastal land area increased by 107.49 km.A variety of human factors contribute for the continuous changes of the coastline.The change in the biotic coastline is mainly the result of competition between mangroves and aquaculture ponds,and the construction of ports and offshore artificial islands,which are also responsible for the land sea pattern reform.Since 2000,the length of the coastline of Hainan Island has increased largely due to the coastal construction projects that have augmented the artificial shoreline.Currently,it is still necessary to strengthen the protection and control of coastlines and promote their sustainable utilization.With the increase in general awareness about environmental protection laws and the implementation of coastal zone management and ecological restoration protocols,the coastal ecological environment will be largely protected and restored.This study contributes to a better understanding of the ecological environmental changes in the coastal zone of Hainan and provides scientific basis for the protection and restoration of its ecological environment.The study provides a scientific application paradigm for the effective use of coastal datasets to conduct research on the coastal environment.