中国地级以上城市紧凑度时空演变特征研究

Spatio-temporal Evolvement of Urban Compactness in China

紧凑城市以提高城市效率为目的,体现在空间结构、社会经济和生态环境3方面。以土地利用紧凑、经济紧凑、人口紧凑、基础设施紧凑、公共服务紧凑和生态环境协同6个维度构建紧凑度综合指标体系,测算2001、2005和2009年中国280个地级以上城市的紧凑度,探讨中国城市紧凑度的时空演变特征。研究发现:①在全国尺度上,中国城市紧凑度整体高降低升,中低紧凑度城市逐渐增多,城市之间的差距不断减小,表现出日益明显的纺锤状特征。②在区域尺度上,紧凑度空间异质性显著,呈东高西低的特征,其中东部地区高紧凑度城市呈团块状分布于京津冀、长江三角洲和珠江三角洲地区;东北和中西部地区低值连绵分布,高值呈斑块状。但从变化趋势来看,东部地区紧凑度逐渐下降,中西部地区则慢慢提升。③城市紧凑度存在明显的规模等级递增效应,超大城市高于大中城市,小城市紧凑度最低。

As a sustainable development strategy that advocates higher urban efficiency, compact urban is of great importance to China cities when it faces a great deal of problems at the stage of fast growing, such as the sprawl of construction land, the short supply of housing residents in urban and incompatible relationship between urban and rural area. To interpret the spatio-temporal characteristics of China cities, the comprehensive evaluation index system is built up based on six dimensions, which are land-use compactness, economic compactness, population compactness, infrastructure compactness, public service compactness and eco-environment coordination. Entropy method was used to calculate the weights of each evaluation index, which the weights of eco-environment coordination and economic compactness are higher than other index. And then we calculate the urban compactness of 280 cities at the prefecture level and above in 2001, 2005 and 2009 based on those weights. The result show that urban compactness elevates slightly overall, and the disparities between cities decreases gradually, which the high scores of urban compactness grow small and the low score of that promote slightly. As to the spatial pattern of urban compactness, the eastern part ranks highest, and follows by the central part and western part of China, which implies the score of urban compactness is relative higher in east and relative lower in west, and that spatial pattern is similar to the spatial pattern of regional economic development. While, referring to the evolvement of urban compactness, the score of the east decreases gradually, and that of central and western part of China elevates step by step. And it is obvious to notice the spatial heterogeneity of urban compactness, the high and low compact cities cluster in different regions. The low value mainly agglomerates in northeastern, central and western China, while the high value mainly locates in eastern China where are Beijing-Tianjin-Hebei area, Changjiang River Delta and Zhujiang River Delta to be more exact. Moreover, that proportion of hierarchies grows even larger with the evolvement, which shows an even more eminent spindle-sized pattern. As to the scale-size characteristics of urban compactness, the megacities have the highest value of compactness that is higher than super cities, large cities and middle-sized cities, and the value of small cities ranks last. It seems to be a strong correlation between urban compactness and urban size, then correlation analysis was used to investigate the result which shows the correlation coefficient between urban compactness and municipal population is below 0.5, which implies a weak correlation.