Analysis of urban thermal characteristics and associated land cover with Landsat TM/ETM+ data in Shenyang, China

Abstract

China has witnessed fast urban growth in recent decades. In this study, remote sensing data from both Landsat-5 TM and Landsat-7 ETM+ were utilized to assess the spatial-temporal characteristics of the urban area in Shenyang in northeast China. To quantitatively determine urban land use extents and development densities, land use/cover were mapped for 8 periods from 1986 to 2007 around the urban and suburban area in Shenyang. The urban-rural boundaries and urban development densities were defined by selecting certain imperviousness threshold values and Landsat thermal bands were used to investigate the thermal patterns of urban surface. Analysis results suggest that urban surface thermal characteristics and patterns can be identified qualitatively based on the urban land use and development density data. Results show that the urban area of Shenyang has an obvious daytime heating effect (heat-source). These thermal effects are strongly correlated with urban development densities i.e. higher percentage imperviousness is usually associated with higher surface temperature. Using vegetation canopy coverage information, the spatial and temporal distributions of urban impervious surface and associated thermal characteristics were demonstrated to be very useful source in quantifying urban land use, development intensity, and urban thermal patterns.