Nonlinear drivers of canopy and surface urban heat islands across China’s climate zones: marginal and interaction effects from explainable machine learning - Cong Wen; Ali Mamtimin; Haitao Wang; Yu Wang; Haotong Liu; Hajigul Sayit; Meiqi Song; Jiacheng Gao; Ailiyaer Aihaiti; Yisilamu Wulayin; Fan Yang; Chenglong Zhou; et al. (Sustainable Cities and Society, 2026)