Thermal Regulation of Urban Waterfront Spaces Across Functional Districts: A Multi-Scale Analysis of Morphological Influences in Chengdu, China Effect

Abstract

Urban waterfront spaces play an increasingly important role in mitigating urban heat and supporting climate-resilient urban development. However, previous studies have primarily focused on individual waterfront sites or local microclimatic simulations, with comparatively limited understanding of how waterfront morphology is associated with land surface temperature across different urban functional districts and spatial scales. This study evaluates the thermal characteristics of fifty representative waterfront samples in Chengdu, China, covering five urban functional districts: commercial, office, residential, park, and suburban areas. Land surface temperature (LST) data for the period from 1 June to 30 September 2023 were integrated with GIS-derived morphological indicators, including river width, water area ratio, green space ratio, building density, and distance to water. Thermal conditions were analysed within the 200 m waterfront zone and across 500 m, 1000 m, and 2000 m buffer zones. Correlation analysis, standardized multiple linear regression, and spatial autocorrelation analysis were used to assess bivariate relationships, independent predictor effects, and the robustness of the statistical results. The results show significant thermal differences among waterfront typologies. Commercial waterfronts exhibited the highest LST, whereas suburban waterfronts showed the lowest temperatures within the immediate waterfront zone. Standardized multiple regression analysis confirmed building density as the strongest independent positive predictor of LST across all spatial scales after accounting for intercorrelations among predictors, with adjusted R2 values ranging from 0.384 to 0.582. River width and the water area ratio were negatively associated with LST mainly within the immediate waterfront zone, whereas the green space ratio showed no statistically significant independent association with LST. Cooling-related thermal contrasts also varied among waterfront typologies across buffer distances; however, inter-typology differences at the 2000 m scale were not statistically significant and should therefore be regarded as preliminary. Spatial autocorrelation analysis further indicated that the principal morphology–LST relationships remained broadly stable after accounting for spatial dependence. These findings suggest that waterfront thermal conditions are strongly associated with the combined configuration of blue, green, and built-environment characteristics rather than with water-body size alone. The multi-scale analytical framework provides a practical basis for evaluating waterfront thermal conditions, while the planning implications should be interpreted as directional rather than as fixed design thresholds.