Association analysis on spatiotemporal characteristics of block-scale urban thermal environments based on a field mobile survey in Guangzhou, China

Abstract

City blocks typically exhibit diverse thermal environmental characteristics due to their self-character complex spatial morphology and lateral thermal interactions from neighboring blocks. A field survey illustrating the spatiotemporal characteristics of block-scale thermal environments is urgently required to explore the inner-associated effects. A mobile survey method was conducted with two selected typical case regions during summer in Guangzhou, China. A block-based local climate zone (LCZ) mapping method was applied to the case regions, and diversified LCZ types that coexist in irregular states were obtained. Then, a multi-step data processing method integrating temporal correction and GIS-based spatial analysis was implemented to obtain the spatiotemporal distribution atlas of air temperature in LCZ blocks. Throughout this study, the air temperatures displayed time-varying characteristics and changed significantly with LCZ types. The correlation analysis showed that the sky view factor and pervious surface fraction present significant positive effects on block-scale air temperature during the daytime. Next, a spatial heterogeneity analysis conducted by fitted semivariogram curves at different times revealed the spatial variability of the urban thermal environment. Additionally, further spatial autocorrelation analysis of thermal interactions between blocks resulted in significant spatial cluster characteristics of air temperatures in the case regions.