Impact of LCZs spatial pattern on urban heat island: a case study in Wuhan, China

Based on World Urban Database and Access Portal Tools (WUDAPT), this study mapped Local Climate Zones (LCZs) in Wuhan in 2020 and detected surface urban heat island intensity (SUHII) within LCZs in day/night of all seasons through Moderate Resolution Imaging Spectroradiometer (MODIS) land products. Four landscape metrics were used to explore spatial heterogeneous effects of LCZs on SUHII by Geographically weighted regression (GWR) model. Results showed that LCZs map can be used to describe the thermal environment in Wuhan. SUHII difference among LCZs was stronger in spring and summer, while less in winter. SUHII difference of the same LCZ was found in three districts in Wuhan. SUHII of most other built classes in Hankou were higher than Wuchang and Hanyang. SUHII within LCZ G in Wuchang was the lowest in daytime of all seasons but the highest at night of all seasons. LCZ 2, LCZ 4, LCZ 5, LCZ 8 and LCZ H had strong positive correlation with SUHII and LCZ D and LCZ G had significant negative correlation with SUHII. Percentage of landscape (PLAND) of LCZs had stronger impact on SUHII than Contagion index (CONTAG), Shannon's diversity index (SHDI) and Area-weighted mean shape index (SHAPE_AM) of LCZs. PLAND of LCZ 8 had strong impact on increasing SUHII in daytime of all seasons, while PLAND of LCZ 2, LCZ 4 and LCZ 5 showed obvious influence on increasing SUHII at night of all seasons. LCZ D had strong impacts on decreasing SUHII in daytime of all seasons and less cooling impacts at night of all seasons. LCZ G showed strong cooling impacts on SUHII in day/night time of all seasons except winter nighttime. SHDI richness of LCZs in analysis unit helped alleviate SUHII. High CONTAG of LCZ with high LST increase SUHII, while High CONTAG of LCZ with low LST decrease SUHII. Very regular shape of LCZ built classes increased the SUHII, while less fragmented of LCZ land cover classes decreased the SUHII.