Detection of urban expansion and land surface temperature change using multi-temporal landsat images

Rapid urbanization in China has attracted the attention of researchers from different countries and regions due to its potential influence on the environment and local climate. In this study, Nanjing City was chosen as a research site to demonstrate the process of urban expansion as well as the associated land surface temperature change in a long time period. Multi-temporal Landsat TM/ETM+ satellite images acquired in April or May in 1985, 1991, 1996 and 2009 were used to document changes in land cover and land surface temperature (LST) using the support vector machine method and thermal image processing. Results showed that Nanjing City rapidly expanded over the study period, with impervious surface area replacing soil and vegetated land. Increasing LST was mostly due to the conversion of LULC change. This study provided an approximately quantification of the magnitude and spatial patterns of urbanization in Nanjing City, and urbanization was shown to be associated with the conversion of vegetative land cover, with likely negative consequences for biodiversity and local climate change.