How does sprawl differ across cities in China? A multi-scale investigation using nighttime light and census data

Timely and accurate measurement of urban sprawl is indispensable for assessing its environmental and societal impacts. However, few studies have examined urban sprawl in cities across China. In this study, we quantified urban sprawl in different cities across China from 1990 to 2010 by combining the Defense Meteorological Satellite Program's Operational Linescan System (DMSP/OLS) nighttime light images and national census data. We found that the annual growth rate of urban areas was 2.45% greater than that of the urban population in China from 1990 to 2010, indicating an overall trend of urban sprawl. Small and medium cities in west China had the highest level of sprawl over time. We conclude that much more attention should be given to the prevention of excessive urban expansion in small and medium cities in west China.