Remote sensing of urban expansion and heat island effect in Jinjiang estuary area of Fujian, China

Over the past twenty years, urban spatial areas in China have expanded in an accelerated speed with the Chinapsilas economic reform. This causes the conversion of the vegetated lands into built-up lands and thus has significant impacts on the ecosystem, biodiversity and local climate. Quanzhou, Jinjiang and Shishi are three cities located in the Jinjiang estuary lowland area of southeast Fujian Province and are famous for their fast economic development. In the meantime, the urban areas of the cities have been growing rapidly. To study the dynamics of the urban expansion for recent 20 years, multi-temporal Landsat TM images of 1987, 1996 and 2006 were used. The mapping of the urban extent was assisted by the Index-based Built-up Index (IBI) through enhancing built-up land features in the images. The multi-temporal analysis reveals that the total urban area of the three cities has greatly increased. This resulted in the development of the urban heat island. The regression statistics indicate that the built-up land has a positive exponential relationship with the land surface temperature (LST). Therefore, the increase in built-up land percentage can exponentially accelerate the rise of the LST.