基于Landsat数据的1975—2015年中国海岸线时空变化分析（英文）

Spatiotemporal changes of the Chinese coastlines:Landsat imageryfrom 1975 to 2015

海岸线是表征陆地和海洋边界的最重要的地理要素,具有独特的地理、形态和动力学特征,海岸带是人类经济活动最活跃和集中的区域之一.在经济发展进程的影响之下,中国海岸线发生了巨大的变化.本研究基于Landsat遥感影像数据,采用改进的归一化差异水体指数,提取了1975—2015年共5期中国海岸线长度及海岸带面积的时空变化信息.结果显示,1975、1990、2000、2010、2015年期中国海岸线的长度分别为15 945.7、17 045.8、17 234.2、17 377.7以及17 364.9km,各期海岸带面积相较于上一期分别增加了4 336.5、1 510.4、3 447.2、3 100.4km2.总体来说,中国海岸线呈现出人工岸线取代自然岸线的趋势.该研究结果可以为沿海区域的资源管理以及海岸规划提供参考.

Coastlines have unique geographical,morphological,and dynamic characteristics describing the most important geographical elements of boundary between land and ocean.Coastal areas are the most active and concentrated places of human economic activities.Coastlines of China underwent tremendous changes under influences of economic development.In this study,we extracted instantaneous shoreline information using a modified normalized water index based on Landsat data from 1975 to 2015,and quantified dynamic changes in terms of length and area.It was found that over the past 40 years,the overall shoreline length had increased steadily,from 15 945.7 km in 1975,to 17 045.8 km in1990,17 234.2 km in 2000,17 377.7 km in 2010 and to 17 364.9 km in 2015.The shoreline area increment as compared with the last period data were 4 336.5,1 510.4,3 447.2,and 3 100.4 km2,respectively.The change intensity varied by provinces.In general,China’s natural coastline had been gradually replaced by artificial coastlines that lead to an increase in land area and coastline length.This phenomenon was largely driven by social-economic activities and had negative impacts on environment and ecology.The present study can be a prototype in efficiently and effectively extracting shorelines.Derived mapping results are valuable to coastal environmental monitoring,urban and regional planning,and resource management.