Characteristics of daytime land surface temperature in wind corridor: A case study of a hot summer and warm winter city

Abstract

With increasing urbanisation, the fraction of built-up areas and human activities increase, deteriorating the urban thermal environment and air quality. To improve the urban environment, wind corridors have attracted much research attention in recent years. In this study, a sky-view factor (SVF)-based method is proposed and verified for the potential wind corridor detection in a built-up urban area. The proposed method accurately identified wind corridors at a spatial resolution as high as 10 m. Characteristics of daytime land surface temperature (LST) were analysed based on Landsat-8 data. Results show that daytime LST in the wind corridor is higher than that in its adjacent non-corridor areas. To quantify the effect of SVF on LST over urban ground-level surfaces, the quantitative relationship between SVF and LST was analysed in the whole study area. Mean LST was found to increase linearly with SVF at a rate of about 0.2 °C per 0.1 SVF value. Moreover, effects of the underlying surface and urban morphology on LST were also discussed. Water bodies were found to effectively reduce LST, whereas in built-up areas, LST was also affected by building height (negative correlation) and building density (positive correlation). When using building height as a variable, the mean LST difference reached 3.5 °C in four seasons, while it was only 1.2 °C between areas with different building densities. These findings are useful to urban planning and provide insights to evaluate wind corridors’ effectiveness holistically.