Multi-scale analysis of surface thermal environment in relation to urban form: A case study of the Guangdong-Hong Kong-Macao Greater Bay Area

Abstract

With the expansion of cities and urban agglomerations, the impact of urban form on the urban thermal environment exhibits notable scale variations. Moreover, the synergistic effect between land surface temperature (LST) and urban heat island intensity (UHII) in urban areas with strong spatial heterogeneity is unclear. Here we explored the spatiotemporal variations of LST and surface UHII (SUHII) over the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) that includes cities of various urban form settings manifested by the local climate zone (LCZ) at multi-scale. The results confirm the LST and LCZ data obtained can effectively capture detailed thermal environment and urban form characteristics for large urban agglomeration (i.e., GBA). Our findings revealed the interactions of LST and SUHII have significant scale disparities. Regionally, the LST and SUHII exhibited strong spatial correlation in built-up area, but showed opposite variation trend in natural areas. At the city scale, the consistency of LST and SUHII is weak in cities with higher vegetation coverage, while strong in cities with lower vegetation coverage. Locally, LST and SUHII exhibited varied interactions in different LCZs. Finally, we proposed corresponding planning recommendations oriented by thermal environment optimization and sustainable development for GBA based on the conclusions.