杭州市半城市化时空格局演变及成因机制研究

Spatial-Temporal Pattern Changes and Formation Mechanisms of Peri-Urbanized Areas in Hangzhou

特大城市半城市化地域的发展关系到国家经济发展、社会稳定和人居环境改善,对其进行主动干预和精明管治势在必行。以杭州市为例,基于土地利用覆盖数据识别半城市化地域及时空格局演变特征,从政府和市场两方面对其成因机制展开解释性研究。发现杭州市半城市化地区呈现出由老城区边缘区向整个中心八区扩展的特征,政策驱动的重大项目带动、市场驱动的乡镇经济推动以及空间管制政策的局限性是杭州半城市化最重要的作用因素。研究旨在解析我国特大城市半城市化发展的客观规律,为相似城市—区域的半城市化地区的管理和规划提供经验借鉴。

Rapid urbanization in China is accompanied by periurbanization in both population and spaces, especially in ultra-large suburbs.Studies have demonstrated that peri-urbanized areas are not only highgrowth belts with extremely high vitality, but also regions with frequent urban expansion, environmental pollution, and social differentiation. Spatial planning might be able to control the abovementioned negative effect effectively.Nevertheless, driving factors of peri-urbanization in China demonstrate diversification as urbanization accelerates. Academic understanding of the inevitability and laws of peri-urbanization have lagged behind practical development and it’s difficult to guide active intervention and smart governance. Therefore, it is vital to study the characteristic laws and driving mechanisms of peri-urbanization in suburbs of ultra-large cities.In the case study based on Hangzhou City, the spatial range of periurbanization was identified using the indexes of "fragmentation of construction land" and "proportion of cultivated lands" based on land-use cover data. "Fragmentation of construction land" is used to explain the "fragmentation and transition" characteristics of peri-urbanization. A total of 7 indexes from four aspects of density, dispersion, polymerization, and shape were chosen using the FRAGSTATS software and a comprehensive fragmentation evaluation model was constructed through principal component analysis(PCA) to estimate the fragmentation index of unit construction in different streets in central Hangzhou. "Proportion of cultivated land" measures the agricultural level of a region by the ratio of cultivated land/constructed land. The above indexes were used to delineate urban areas, peri-urbanized areas, and agricultural areas. On this basis, the spatial-temporal pattern evolutionary characteristics of peri-urbanization in central urban area in Hangzhou were summarized from the perspectives of overall pattern, development characteristics, type differences, and future trends. Finally, attention was paid to explaining driving mechanisms of peri-urbanization in centralHangzhou from perspectives of government and market.Research results demonstrated that(1) from 2000-2015 the periurbanized areas in Hangzhou expanded from edges of the old urban area to the eight central areas.(2) The fast construction of peri-urbanized areas in Hangzhou didn’t attract corresponding population growth and there is a "spatial dislocation" in the man-land relationship.(3) The peri-urbanized areas in Hangzhou were divided into four types: continuous type, fluctuating type, newly increased type, and reduction type. The fluctuating type and reduction type reflect the fast expansion of special policy regions like Beinjing and Dajiangdong New City, as well as continuous expansion of urban areas.(4) The case in Hangzhou shows two possibilities for peri-urbanization in future: "complete urbanization" and "sustainable peri-urbanization".(5)Policy-driven project promotion, market-driven rural economic promotion,and limited spatial administration policies might be the most significant mechanisms of peri-urbanization in Hangzhou.This study aimed to analyze objective laws of peri-urbanization in suburbs of ultra-large cities in China and provide data for management and planning of peri-urbanization in similar regions. Significantly, the case study in Hangzhou has some universality with the Yangtze River Delta area. However, it may be inapplicable to northern China where stronger policy is in effect and southern China where this is greater social power. Moreover, case study results are difficult to apply to middle and western China where development has lagged.