Beyond flat cities: dramatic 2D/3D differences in urban gray–green space configurations and the nonlinear thermal regulation mechanisms

作者：Xi Wang, Liang Zhou, Yongze Song, David López‐Carr, Shaohua Wang, Hong Chen, Hongwei Gao, Rongfang Lyu, Qinke Sun, Zecheng Guo, Wei Wei · 发表于：GIScience & Remote Sensing · 年份：2025 · DOI：10.1080/15481603.2025.2572174 · 被引用次数：4 · 研究领域：Urban Heat Island Mitigation、Urban Green Space and Health、Land Use and Ecosystem Services

Traditional 2D morphological indicators are inadequate for characterizing vertically expanding cities, which hampers the identification of key predictors of urban heat under extreme temperatures and within the complex interactions between gray and green spaces. Therefore, we developed a suite of multidimensional morphological indices and leveraged an XGBoost-SHAP framework to decipher the complex, nonlinear relationships and synergistic interactions between these indices and land surface temperature (LST). We selected Xi'an, the only megacity in Northwest China, as a case study and introduced Lanzhou as a case for verifying transferability. The findings revealed the following: (1) Within the Xi'an Ring Expressway, 73.84% of the blocks underestimated the relationship involving 3D gray and green space configuration, while this proportion was higher in the Lanzhou main urban area, and the underestimated regions were concentrated in the core area of high-density cities. Spatial variations in 2D and 3D gray–green ratios (GGR) effectively delineate urban functional zoning. (2) Counterintuitively, average building height (ABH) emerged as the most critical factor influencing LST. At the same time, 3D indicators contributed 1.86 times more to LST changes than 2D indicators. (3) The complex nonlinear correlation between urban spatial morphology and LST is exhibited, and the marginal effect results reveal the key threshold of urban spatial morphology indexes affecting LST, 3D GGR is mor...