Effect of blue-green landscape pattern and urban forms on surface urban heat island intensity: Evidence from 816 Chinese urban clusters
Siyuan Li, Yuxin Liang, Dewei Yang, Jingwei Shen
Abstract
• Daytime and nighttime SUHII show distinct variations across different climate zones. • Daytime SUHII is more influenced by impervious surfaces, while nighttime SUHII is more affected by precipitation. • Blue-green landscape with higher dominance and lower fragmentation better mitigate SUHII. • Optimization of blue space landscape is more crucial in arid regions. With economic development and urban expansion, the surface urban heat island (SUHI) effect has become increasingly pronounced. As blue-green landscapes are recognized as an effective means of mitigating SUHI, it is particularly important to study the impacts of blue-green landscape pattern and urban forms on both daytime and nighttime surface urban heat island intensity (SUHII). However, at the urban scale, comprehensive studies that simultaneously consider blue-green landscapes and urban forms, as well as investigations into their specific impact mechanisms on SUHII, remain limited. Therefore, this study uses 816 urban clusters in China as research cases, combining the Extreme Gradient Boosting (XGBoost) model with the Shapley (SHAP) method to explore the impact of blue-green landscape pattern and urban forms on SUHII at the urban scale. The results are as follows: The SUHII of cities in different geographic regions is primarily determined by their background climate and topography, followed by urban forms, and finally by blue-green landscape pattern. Cities with higher impervious surface ratios, greater building heights, and stronger aggregation exhibit more pronounced SUHII. In contrast, cities with greater dominance and lower fragmentation of blue-green landscapes are generally associated with lower SUHII.