The Research of China Urban Efficiency Based on Suomi-NPP Night-time Light Data

China is the fastest urbanizing area in the world. Nowadays, increasingly complex urban systems not only create more socioeconomic output (such as GDP), but also bring more infrastructural costs, which intensifies the contradiction between large populations and relatively scarce resources. Thus, urban research has to focus on urban efficiency toward efficient, inclusive, and sustainable urbanization instead of urban size. Aiming at “land” in man-land relationship, urban size research mainly explores location factors. However, proposed by Michael Batty, social interaction is the driving force for urban efficiency, stressing on “man” in man-land relationship. Recently, our increasing ability to collect and share data on many aspects of urban life has begun to supply us with better clues to the properties of cities. Human activity can be effectively reflected using night-time light imageries. Making use of Suomi-NPP night-time light data, the Night Light Urban Efficiency Index (NLUEI) was proposed to quantitatively evaluate the urban efficiency, then this index was applied to 282 cities in China to calculate their urban efficiency. Results showed that 60.5% of these cities obtained the same result via NLUEI and social-tie density model from MIT. Compared to “2013 urban competitiveness blue book” published by CASS (Chinese Academy of Social Sciences), seven cities in top ten cities published by CASS also emerged in top ten cities according to NLUEI, and other three cities were all energy cities with low NLUEI. It is demonstrated that (1) NLUEI is a straightforward and objective index for evaluating the urban efficiency and (2) NLUEI works well in China and has great potential in urban management.