北京城郊化空间特征与发展对策

城郊化是大都市生命周期中的重要阶段之一，20世纪90年代以来北京进入了典型的城郊化过程。根据1985－2000年遥感影像和1992－2000年2000多个土地开发样本资料，在GIS的支持下，通过对比北京80－90年代城郊化空间特征，概括出城市用地5种扩展方式和廊道效应作用下的波浪式扩展过程。在模拟分析的基础上结合北京举办2008年奥运会带来的巨大投资规模，预测北京大都市城郊化的3个圈层、8个扇面和6条廊道的发展趋势。

Spatial Characteristics of Suburbanization and Its Developing Strategies in Beijing

Centralization, Sub-urbanization, Counter-urbanization and Re-urbanization are the main phases in the life cycle of metropolis. Sub-urbanization is one of the most important stages in metropolitan development. There have been four tidal waves of sub-urbanization in western developed countries since the 1930s. The analyses of sub-urbanization in this paper provide some of conclusions supported by TM images in Beijing from 1985 to 2000 and GIS as well as 2000 samples of land developing markets from 1992 to 2000. There were multi-growth patterns in urban spatial growth from the analysis. At the same time, by studying the Beijing's spatial extension pattern in central urban area hi different periods, five growth or diffusion types were identified. The analysis indicates that excessive land use transformation from rural area to urban area was the result of distinct center and corridor effects. This paper analyses the corridors' extension volume, extension velocity and variant tendency of urban landscape on several directions. Finally, it is illustrated that three concentrated regions, eight developing sectors and six radiate corridors have been or will be formed from 2000 to 2010. Moreover, this paper brings forward the idea of incorporating the system of natural corridors into the Beijing's metropolitan planning, namely to form a star-shaped scattering-group pattern in which artificial corridors and natural corridors are alternately distributed in order to effectively prevent built-up area from massive growth and to meet the sound environmental needs of 2008 Olympic Games.