苏州地区城镇扩展的空间格局及其演化分析

Urban Spatial Growth Pattern and Its Evolution in Suzhou,Jiangsu Province,China

基于苏州地区1984-2005年的6个时相卫星遥感数据,从城镇实体地域扩展的视角,运用关联分维数、全局和局域空间关联指数、空间变差函数等方法构建了空间关联测度模型,分析了苏州地区城镇扩展的周期性、城镇建设用地的分维特征、城镇扩展的"热点区"空间分布及演化,城市化空间梯度的形态演化。结果表明,20世纪80年代以来,苏州地区的城镇扩展经历了稳步增长、缓速下降、急速增长和快速下降四个阶段,显示出"大起大落"的特征;在空间格局上,城镇扩展强度的高值簇区(热点区)呈现出较明显空间演化和跃迁的特征,经历了苏州市区、苏州—吴江轴线、苏州—昆山轴线(沿沪宁线)、太仓—常熟—张家港轴线(沿长江)的不断轮换,并成为不同阶段驱动苏州地区社会经济发展的核心区。期间,城镇扩展的空间连续性和自组织性越来越强,城市化发展的空间形态由相对分散向相对集中演化,由空间自相关引起的结构化分异的机理越来越显著,并且表现出较明显的带状关联特征,城市区域化发展的趋势明显。然而,在苏州地区不同的发展阶段,城镇发展的主导驱动机制有所不同。

An integrated model for spatial association metrics is developed on the basis of fractal correlation coefficient, global and local spatial association measurements, and semivarigram. And six input data for the model are acquired by multi-source satellite imageries covering the period 1984-2005, including Landsat TM or ETM, 1RS-P6. Then, we used the model to study the urban growth periodicity, the fractal dimensions of the built-up area, the spatial distribution and evolvement of the ＂hot spot＂ districts of urban growth as well as the pattern evolution of spatial gradient since the reform and opening-up of China. Finally, some conclusions are drawn as follows. （1） Since the 1980s, Suzhou＇s urban growth has experienced four stages from a gradual increase, a slow decrease, then a rapid rise to a sharp decline..（2） There exists an obvious characteristic of spatial evolution and shift according to the analysis of high-value clusters, viz. ＂hot spots＂, of urban growth intensity. The hot spot of urbanization is in turn from 1984 to 2005, going from Suzhou city, Suzhou city-Wujiang axis to Suzhou city-Kunshan axis along the Shanghai-Nanjing expressway, and then to Taicang-Changshu-Zhangjiagang axis along the Yangtze River. These hot spot regions are the cores driving social and economic development in differenrt periods in Suzhou. In the development period, spatial continuity and self-organization of urban growth has been intensified, and the spatial form of urbanization changed from decentralization in the initial stage to centralization at present. Additionally, the structural difference due to spatial association becomes more and more obvious with a characteristic of strip association, showing a tendency of a regional urbanization. It is worth noting the fact that the driving force of urbanization is different in different stages.