Investigating the diversity of land surface temperature characteristics in different scale cities based on local climate zones

The concept of Local Climate Zones (LCZs) are effective tools to quantify the urban heat island effect. However, the study of LCZs mainly focuses on the meso-micro scale, and lacks regional perspective. In order to explore the thermal environment laws of different sized cities, we selected the Pearl River Delta urban agglomerations as the study area, and used multi-source data and spatial analysis methods to obtain the thermal environment characteristics of each city based on LCZs. Our study revealed that the distribution of buildings and the relief slope affects land surface temperature (LST). Additionally, the proportions of various LCZs are different in cities of different sizes; each city had a temperature difference in the LCZs. The highest temperature among the built LCZs was in LCZ 7 (Industry; 21.810 °C), whereas the temperature of LCZ A (Dense trees) was the lowest (15.670 °C), and larger cities had more high-temperature LCZs. In cities of different sizes, the temperature of LCZs showed a hierarchy effect, i.e., super cities > megacities > type I large cities > type II large cities. Therefore, in order to alleviate the urban heat island effect, it is of great significance to discover the thermal environment characteristics in cities of different sizes.