面向对象方法和多源遥感数据的杭州湾海岸线提取分析

Coastline Changes in Hangzhou Bay Based on Object-oriented Method Using Multi-source Remote Sensing Data

本文以1983-2011年的多源遥感数据为基础,利用GIS空间分析和地图代数功能,提取杭州湾海岸线,分析了其变迁的位置、长度,以及增加和减少的陆地面积。结果表明:受到自然和人为因素的影响,杭州湾南北两岸的海岸线变迁规律不同。杭州湾北岸1983-1993年共有60.2km的海岸线向陆迁移,最大迁移距离0.6km,减少的陆地面积共为23.5km2。1993-2011年由于围垦和工业填海北岸向海迁移。其中,1993-2002年最大迁移距离3.6km,新增陆地面积42.5km2,2002-2011年最大迁移距离2.9km,新增陆地面积61.0km2。由于淤积和围垦,杭州湾南岸海岸线不断向海迁移,1983-1993年、1993-2002年和2002-2011年向海迁移最大距离分别是1.8km、2.7km和5.1km,新增陆地面积分别为34.3km2、230.2km2及331.7km2。海岸线向海迁移的速度越来越快,规模越来越大。研究成果对于地图制图、滨海湿地生态资源管理,以及海岸线保护具有十分重要的意义。

The coastline is defined as the line of contact between land and a body of water. Coastline change detection is critical issues for coastal resource management, coastal environmental protection, and sustainable development and planning. Changes of coastline may be caused by natural processes and/or human activities. Over the past 30 years, the coastal sites in Hangzhou Bay have been under an intensive restraint associated with population growth and economic development. This study introduced object-oriented classification method to monitor coastline changes in Hangzhou Bay using multi-source remote sensing data, i.e., Landsat Multispectral Scanner （MSS） image in 1983, Landsat Thematic Mapper （TM） image in 1993, Landsat Enhanced Thematic Mapper Plus （ETM ＋） image in 2002, and Environment Satellite Charge Coupled Device （CCD） image in 2011. Results showed that, from 1983 to 1993, there was 60.2 km northern coastline moved landward with the maximum distance of 0.6 km and a lost area of 23.5 km2, because of the coastal erosion. And from 1993 to 2011, the northern coastline moved seaward because of land reclamation and construction. From 1993 to 2002, this part of coastline moved seaward with the maximum distance of 3.6 km and 42.5 km2 filled up areas. From 2002 to 2011, it moved seaward with the maximum distance of 2.7km and 61.0 km2 filled up areas. From 1983 to 1993, natural processes were the main reasons for northern coastline recession. During the study periods, southern coastline of Hang-zhou Bay moved seaward caused by sedimentation and land reclamation. From 1983 to 1993, 1993 to 2002, and 2002 to 2011, this coastline moved seaward with the maximum distance of 1.8km, 2.7 km and 5.1 km, respectively, and with area of 34.3 km2, 230.2 km2 and 331.7km2 sea surfaces turned into mainland, respectively. Southern coastline moved seaward was the result of natural processes and human activities. From 1983 to 2011, the filled up areas were growing faster and larger. The result of this study can provide valuable information for Hangzhou Bay coastline dynamics and may assistant to the coastal land management and sustainable development and planning.