Ecological Indicators (Feb 2024)
Seasonal surface urban heat island analysis based on local climate zones
Abstract
A fundamental aspect of ensuring urban sustainability is a comprehensive understanding of the driving mechanisms behind the urban heat island (UHI) phenomenon. The primary objective of this study is to investigate the spatiotemporal variations and underlying mechanisms of the surface urban heat island (SUHI) in Hefei. The study employed the local climate zone (LCZ) method to analyze land surface morphology and spatial structure for 2014 and 2021. Subsequently, calculations were conducted to derive surface urban heat island intensity (SUHII), normalized difference built-up index (NDBI), normalized difference vegetation index (NDVI), gravity water index (GWI), building surface fraction (BSF), road density (RD), poi density (PD), and population density (PPD). The exploration of the mechanisms by which factors influence SUHI was conducted by utilizing both Pearson correlation analysis and geographic detector models. The results revealed that sparsely built (LCZ 9) and low plants (LCZ D) predominantly characterized built-up and natural coverage areas, respectively. The summer season was distinguished by the most extensive SUHI distribution and the highest SUHII levels. Significantly, SUHII consistently exceeded those of built-up LCZs when contrasted to natural LCZs. Large lowrise (LCZ 8) consistently displayed the highest SUHII levels, whereas water (LCZ G) consistently exhibited the lowest SUHII values. NDBI took precedence and showed a positive correlation with SUHI. Among the socio-economic factors, building height (BH) demonstrated a superior explanatory capability for SUHI compared to other variables. The interaction between NDBI and NDVI maximized the explanation of SUHI under different seasons. The findings of this study will serve as critical insights for urban planners and policymakers, enabling the development of scientifically-based and efficacious strategies to mitigate SUHI.
