选取1973年-2013年多源遥感影像为数据源,以深圳、厦门、海口为例,开展中国经济特区城市建城区的长时序、高频数空间扩展遥感监测。选取城市扩展速度、城市扩展对土地利用的影响、城市形态紧凑度和城市重心迁移作为指标,剖析经济特区城市扩展的时空特征,耦合自然要素与人为要素,对比分析深圳、厦门和海口在城市扩展过程中表现出来的异同,并探讨其原因。结果表明:(1)近40年来,经济特区城市扩展先后经历了一个缓慢平稳扩展阶段、两个加速扩展阶段和两个减速扩展阶段。深圳的扩展速度最快,其次是厦门,海口的扩展速度最慢;(2)耕地对经济特区城市扩展贡献最大,林地、水域、城乡工矿和居民用地、海域也是经济特区城市扩展的重要土地来源,草地和未利用土地的贡献最小;(3)经济特区城市的空间形态总体趋于松散,1973年-2004年城市紧凑度剧烈降低,2004年之后趋于平稳;(4)在政策与填海造地工程的共同影响下,经济特区城市重心有向海岸线方向迁移的趋势,深圳的迁移量最大,海口最小。

With the formulation of different policies, special economic zones dramatically expanded in the past 40 years. Basing from remote sensing and geographic information system technology, we performed long-term and high-frequency monitoring of urban expansion in special economic zones by using multi-source remote sensing images between 1973 and 2013. Shenzhen, Xiamen, and Haikou were selected as research subjects. All spatial expansion information was obtained through human-computer interactional digital interpretation. Basing from established-interpretation symbols of urban lands, researchers with experience in visual interpretation referred to Google Earth and topographic maps to ensure the accuracy of monitoring results above 90%. This study selected expansion speed, influences on land use, compact ratio, and centroid shift as indicators, and combined the effects of natural and man-made elements to analyze the similarities and differences of spatiotemporal characteristics among Shenzhen, Xiamen, and Haikou. Four major results were obtained. First, the expansion speed of special economic zones in the past 40 years experienced one low-speed stable stage, two acceleration stages, and two deceleration stages. The expansion speed of Shenzhen was the fastest, followed by Xiamen and then Haikou. This situation fully reflects the significance of national and local policies, as well as social and economic development. Second, 1370.61 km² nonurban lands around Shenzhen, Xiamen, and Haikou were converted to urban land between 1973 and 2013. Arable land was the first land source of special economic zone urban expansion. Other main land sources of urban expansion include forest land, water body, rural settlement, industrial and traffic lands, and sea area. Grassland and unused land had minimal contribution to urban expansion. Rural settlement and industrial-traffic land was the second land source of Xiamen and Haikou urban expansions, and the third land source of Shenzhen urban expansion. Forest land was the second land source of Shenzhen urban expansion but produced a contribution rate of <10% to Xiamen and Haikou. Third, the compact ratio of special economic zones decreased. Before 2004, land resources around special economic zones were relatively adequate, urban expansion was fast, land-use efficiency was low, and compact ratio considerably reduced. After 2004, urban expansion space was limited, expansion speed slowed down, and compact ratio stabilized. Fourth, marine reclamation engineering appeared during urban expansions in Shenzhen, Xiamen, and Haikou. Under the combined effects of the policies and marine reclamation engineering, the centroid of special economic zones tended to migrate toward the coastline. Affected by the comprehensive influence of expansion area and compact ratio, Shenzhen and Haikou had the large stand smallest centroid shift distances, respectively. Remote sensing monitoring of expansions in special economic zones can provide support for the future projection and policy formulation of special economic zones.