Urban morphology, encompassing both horizontal landscape patterns and three-dimensional architectural structures, plays a pivotal role in modulating urban heat distribution. However, conventional models often fail to capture the intricate spatial nonstationarity and nonlinear coupling of these drivers at the block scale. Recognizing that land surface temperature (LST) exhibits distinct diurnal and nocturnal thermal cycles, this study explicitly incorporates spatial heterogeneity analysis to systematically evaluate the relative and local contributions, marginal effects, and interaction mechanisms of multidimensional urban morphology on diurnal LST variations. To achieve this objective, geographically weighted extreme gradient boosting and SHapley Additive exPlanations were employed to decipher these complex driving mechanisms from a morphological perspective. The results indicate the following: (1) Built environment variables predominate the spatial heterogeneity of LST in Xi’an, China, with their governing mechanisms shifting diurnally—characterized by a midday NDVI-induced evapotranspiration cooling effect and an atmospheric back-radiation warming effect associated with PM2.5 during the night and early morning. (2) The driving mechanisms exhibit pronounced spatial nonstationarity; while the northeastern and northern sectors are primarily influenced by the synergistic interaction between surface albedo and PM2.5, the central-western and southern regions are governed by population density and 3D architectural morphology. (3) Significant nonlinear interaction thresholds and non-monotonic response mechanisms were identified across the variables. By resolving localized thermal responses through the lens of spatial heterogeneity, this research provides a robust scientific framework for precision urban planning and the mitigation of the urban heat island effect.
Huang et al. (2026) studied this question.