Local Climate Zone-Based Analysis of Urban Heat Island Influencing Factors in Coastal Cities Across Multiple Climate Zones

Abstract

Highlights: What are the main findings? The spatial distribution of SUHII and the role of influencing factors in urban heat islands. Coastal SUHII is regulated by land–sea interactions and nearshore marine cooling, with thermal responses varying by climate zone. What are the implications of the main findings? The findings advance the understanding of multi-scale drivers of coastal SUHI and provide a scientific basis for climate-adaptive urban planning strategies that optimize coastal morphology. The results offer theoretical support for developing differentiated planning strategies in coastal cities and guiding the optimization of urban spatial elements to maximize the use of marine cooling effects. Rapid urbanization has intensified the Surface Urban Heat Island (SUHI) effect, which poses particular challenges for coastal cities where marine environments, climatic regulation, and distinctive urban morphology interact in complex ways. Current research on coastal SUHI remains limited, especially in terms of systematic analyses using the Local Climate Zone (LCZ) framework. Key gaps include insufficient cross-climate comparisons and limited understanding of spatial differentiation patterns linked to LCZ-based SUHI dynamics. This study employs LCZ classification to analyze coastal cities across diverse climatic backgrounds, integrating Pearson’s correlation analysis and coastal distance gradient zoning to investigate the spatio-temporal distribution and influencing factors of Surface Urban Heat Island Intensity (SUHII). The findings reveal that: (1) SUHII exhibits a distinct spatial pattern, with elevated intensities in built-up areas and reduced values in natural zones, alongside seasonally differentiated variations across climate zones. (2) The normalized difference built-up index (NDBI) and normalized difference vegetation index (NDVI) emerge as dominant drivers, exerting heating and cooling effects, respectively. Elevation alleviates SUHII, whereas anthropogenic factors dominate during summer. (3) Coastal SUHII is governed by dual regulatory mechanisms: land–sea interactions modulate spatial patterns, with NDVI cooling and NDBI heating effects amplifying with distance from the coastline, while nearshore marine regulation suppresses heat accumulation. Additionally, cities across different climatic zones exhibit distinct thermal responses, with vegetation cooling efficiency and building-induced heating intensity showing clear latitudinal gradients. These findings advance understanding of multi-scale drivers of coastal SUHI and provide a scientific basis for climate-adaptive urban planning strategies that optimize coastal morphology.