Scale-dependent effects and thresholds in urban climate regulation: The roles of local and surrounding environmental influences
Journal
Urban Climate
Journal Volume
70
ISSN
2212-0955
Date Issued
2026-12
Author(s)
Chang, Han-Chin
Abstract
Urban green spaces are widely recognized as effective nature-based solutions for mitigating the urban heat island effect. Although previous studies have highlighted the spatial continuity and dynamic characteristics of climate regulation services, most have relied on single-scale assessments, limiting understanding of how environmental characteristics influence urban thermal conditions across spatial extents. This study investigated the effects of local- and neighborhood-scale environmental characteristics on air temperature (Ta) and mean radiant temperature (Tmrt). Ta and Tmrt at different times of day were simulated using ENVI-met, and generalized additive models were applied to quantify scale-dependent relationships across scales. The relative contributions of environmental variables and the threshold values for effective cooling were subsequently evaluated. The results revealed distinct scale-dependent responses for the two thermal indicators. Ta was best explained by neighborhood-scale environmental characteristics within a 200 m buffer, whereas Tmrt was most strongly associated with nearby environmental conditions within a 50 m buffer. Neighborhood-scale variables generally contributed more to Ta than local variables, whereas daytime Tmrt was primarily associated with local tree canopy cover together with neighborhood-scale urban form, reflecting the combined effects of shading and the pedestrian-scale radiation environment. Clustered tree canopy cover showed the strongest cooling effect on Ta, with effective cooling occurring at approximately 10% cover, whereas dispersed canopy required approximately 17% cover to achieve a comparable cooling response. In contrast, Tmrt exhibited nonlinear threshold responses to tree canopy cover and floor area ratio. These findings provide references for scale-sensitive urban greening strategies and climate-responsive urban planning and design. © 2026 Elsevier B.V.
Subjects
Cooling effect
Ecosystem services
ENVI-met
Generalized additive model
Spatial extent
Urban green space
Publisher
Elsevier BV
Description
Article number 103153
Type
journal article