Spatiotemporal characterization of the urban sprawl and its impacts on urban island in China with DMSP/OLS and MODIS measurements

The rapid development of cities has led to the urban sprawl to the suburbs. Studies have shown that urban sprawl leads to the increasing intensity of heat island effect. This paper, based on the DMSP/OLS nighttime light data and the MODIS land surface temperature data during the years 2000, 2005, and 2013, discussed the spatial and temporal characteristics of urban sprawl, urban heat island intensity in China, and their relationship, respectively. The results show that (1) the national urban expansion index showed an upward trend. The urban area was 104,000 km2 in 2000, 169,000 km2 in 2005, and 312,000 km2 in 2013.The average annual growth rate was 10.2% in 2000–2005, 8% in 2000–2013, and 8.8% in 2000–2013. (2) The national heat island index also showed an upward trend; total heat island intensity was 716.73 °C in 2000, 812.84 °C in 2005, and 995.46 °C in 2013. The annual average growth rate was 2.55% in 2000–2005, 2.57% in 2005–2013, and 2.56% in 2000–2013. (3) There is a positive correlation between urban spatial expansion and heat island intensity in China. The urban and suburban range of China can be objectively extracted from the DMSP/OLS nighttime light data every year and superimposed with the MODIS land surface temperature data of the same period, which ensures the correctness of the urban heat island intensity based on the actual changes of suburban areas and main urban areas in each city, and overcomes the calculation error of the traditional method, which neglects that some suburbs have become urban areas and are still regarded as suburbs. These results provide spatiotemporal changes characterization of urban area in China during recent decades, which are helpful in decision-making of land management and planning for sustainable development.