A gradient analysis of urban heat environment pattern - A case study from Zhujiang Delta

Quantifying land use/cover and its ecological consequences in urban area is essential in urban environment science, geography and urban ecology. Land surface temperature is undoubtedly one of the most significant parameters in urban. The distribution pattern characteristic of heat environment, which is the indicator of ecological process of urban landscape changes and environmental effect, deserves thorough research. In this paper, taken Zhujiang Delta as the study area, we derived the land surface temperature at the pixel size of 30 m× 30 m from Landsat TM image in 2006. Landscape metrics and gradient analysis of heat environment pattern in Zhujiang Delta were employed and compared. A transect, which is 150 km long and 10 km wide was established across east to west in the central including Foshan, Guangzhou and Dongguan. The results show that heat environment pattern along urbanization area could be quantified and detected by the method of landscape metrics and gradient, different heat landscapes show their gradient characteristics along urban-rural gradient obviously. In class level, the percentage of landscape and patch density of high temperature, sub high temperature and low temperature show their gradient characteristics apparently. High temperature type was the dominant class in urban core, while sub medium temperature and low temperature type was the main heat landscape type in rural area. In landscape level, different metrics showed quite diverse. In the urban fringe, heat pattern showed very complex result from the various land use. The study also confirms that the approach of integration of landscape metrics and gradient analysis is reliably a useful tool to monitor the heat environment pattern along urban-rural transect.