A comparative analysis of megacity expansions in China and the U.S.: Patterns, rates and driving forces

• Published in: Landscape and urban planning Vol. 132; pp. 121 - 135
• Main Authors: Kuang, Wenhui, Chi, Wenfeng, Lu, Dengsheng, Dou, Yinyin
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.12.2014; Elsevier
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; China; Conservation, protection and management of environment and wildlife; Decay; Driving conditions; Economic conditions; Fundamental and applied biological sciences. Psychology; General aspects; Impervious surface area; Landscapes; Megacities; Surface area; Urban expansion; Urban planning; Urbanization; USA; Asia; United States; North America; China; America; USA, Illinois, Chicago; China, People's Rep., Guangdong Prov., Guangzhou; USA, New York; China, People's Rep., Beijing; USA, California, Los Angeles; China, People's Rep., Shanghai; Urban expansion; Megacities; Impervious surface area; USA; China; Analysis; Urban area; Surface area; Expansion; Environmental management
• ISSN: 0169-2046; 1872-6062
• DOI: 10.1016/j.landurbplan.2014.08.015

•Chinese megacities have five times higher urban expansion in area than American megacities in past three decades.•Chinese megacities have obvious urbanization patterns and rates at temporal scale but American megacities do not have.•Chinese megacities expand from urban to rural with concentric rings but American megacities fill open spaces within inner cities.•Chinese megacities are in developing stage that population, economic conditions and policies affect urbanization patterns and rates.•American megacities are in developed stages without obvious impacts from population, economic conditions and policies. Research on physical characteristics and land-cover dynamic changes of megacities over time provides valuable insights for effectively regulating urban planning and management. This study conducts a comparative analysis of 30-year urban expansion patterns and rates among three metropolises in China (Beijing, Shanghai, and Guangzhou) and another three in the USA (New York, Los Angeles, and Chicago) based on time-series impervious surface area (ISA) data extracted from multitemporal Landsat images using the linear spectral mixture analysis approach. This research indicates significantly different urbanization patterns and rates between the Chinese and American megacities. The ISA expansion area in Chinese megacities was five times higher than that in American megacities during the past three decades. The Chinese megacities expand outward from the urban core to the periphery in a concentric ring structure, whereas the American megacities increase ISA mainly within the inner cities with patch-filling patterns. The Chinese megacities are in the development stage where population and economic conditions significantly influence urban expansion patterns and rates, but the American megacities are in the developed stage where population and economic conditions are not important forces driving the ISA expansion. The ISA intensity in the American megacities decreases constantly and smoothly, but ISA intensity in Chinese megacities decays abruptly within certain distances, depending on different cities and years. The most obvious urban expansions were between 8 and 20km in Beijing in the 1980s, between 14 and 50km in Shanghai in the 2000s, and between 8 and 18km in Guangzhou in the 1990s.