Surface urban heat island effect of local climate zone

Abstract:

To study the effects of urban form and land cover on the surface urban heat island (SUHI), by taking Xi’an as an example, local climate zone (LCZ) and land surface temperature (LST) inversion methods were employed to investigate the LST distribution of different types of LCZ based on the Landsat8 remote sensing and building vector data. Results show that the LST of the built-up LCZ was higher than that of the land cover LCZ, but the temperature variation of the built-up LCZ was more stable than that of the land cover LCZ. In built-up LCZ, LST increased with the increase of building density. In land cover LCZ, the LST of water was the lowest, while the LST of bare land was the highest, and LST of three types of vegetation LCZ were lower than those of other two types. LST and SUHI intensity of 14 samples were also calculated. Urban form indicators of built-up LCZ were introduced to analyze the effect of urban form on the SUHI, including building surface fraction (BSF), ratio of green space (GSP), and height of roughness elements (HRE). In built-up LCZ, high-rise buildings with high density and greening could reduce LST and alleviate the SUHI effect. SUHI intensities of water body and forest were lower than those in land cover LCZ types. SUHI effect could be alleviated by increasing water body and greening and reducing building density. The use of shading devices to reduce solar radiation could also mitigate the SUHI effect.