Influence of land use change on urban heat island derivedfrom multi-sensor data

摘要

Regional climate change was demonstrated to be likely influenced by anthropogenic dominated land surface processes. Urban heat island (UHI) is one of the important outcomes of such land surface processes induced by urbanization, and it is an urban climate phenomenon influenced by land use pattern and it represents the difference in albedo, roughness, and heat flux exchange of land surface. This study tries to examine the influence of land use change on UHI in greater Guangzhou from 1980-2007 by analysing Landsat MSS/TM/ETM+ and MODIS satellite data, meteorological records, and census data. An integrated and modified single-channel method was used to retrieve land surface temperature (LST). Decadal changes in land use fraction and UHI pattern show that cropland decreased in parallel to the increase in built-up area and the correlation coefficient reached 0.97. The UHI effect expanded from urban areas to surrounding suburban areas and countryside with an increase in land surface temperature (mean LST increased by 2.48 from 1990 to 2007) and a decrease in the green vegetation fraction (GVF) (mean GVF decreased by 0.16 from 1990 to 2007). The spatial heterogeneity of UHI expansion can be explained by spatial patterns of economic development, population increase, and abundance of vegetation cover. In addition, remarkable changes in air temperature due to relocation of meteorological stations are significant signals for detecting the influence of urbanization on urban heat island.