Evaluating the local climate zone classification in high-density heterogeneous urban environment using mobile measurement

Urban heat island (UHI) has been identified as a threat to urban living quality in the context of climate change. As awareness of the impacts of urban expansion on local climate increases, urban planners/decision makers attempt to incorporate climatic considerations into the planning process. An increasingly-used urban climatic analysis scheme- Local Climate Zone (LCZ) classification- has been applied in Hong Kong, a high-density city with heterogeneous an urban environment. This study aims to evaluate the LCZ mapping in such a unique urban context using in-situ air temperature data. The fine-scale spatial variation of the daytime and nighttime screen-level air temperatures was investigated via mobile measurements during the summertime of 2016. The measured data were collated in Geographic Information System (GIS) based on the current LCZ maps. Statistically significant air temperature differences were observed between most LCZ classes, which confirm the veracity of LCZ in high-density heterogeneous urban contexts. Higher uncertainties in the site-averaged air temperature and considerable intra-LCZ air temperature differences in LCZs 1 to 6 were observed. It indicates that the current LCZ procedures of Hong Kong can be further refined for a better understanding of the climatic heterogeneity in densely built urban areas.