GIS-Based Urban Morphology Indicators for Assessing Urban Heat Island (UHI) Effect

Urbanization, marked by the increasing concentration of population in urban areas, has evolved into a global phenomenon with far-reaching implications for societies. The recognition of the relationships between urban morphology and the urban heat island (UHI) effect is essential for the effective mitigation of UHI in cities. This study employed a comprehensive approach, integrating Geographic Information System (GIS)-based analysis, Pearson correlation, and stepwise regression methods, to calculate four morphological parameters, aiming to explore their impact on temperature variations. By focusing on Bologna city in Italy as the study area, significant discoveries emerge, including (1) Positive correlations were found between temperature and building height, density, and floor area ratio, while a negative correlation was observed with the percentage of vegetation. (2) Spatial patterns revealed a consistent trend across all four indices, indicating that temperature variations are more pronounced in the city center and gradually decrease when moving towards the west or south. This uniformity underscores the concentrated influence of urban morphology on temperature dynamics in specific regions of Bologna, particularly in the city center where tall buildings, high building density, and limited green areas contribute to increased temperatures. (3) Building density emerged as the most influential factor affecting temperature variations among the morphological parameters studied. Higher building density was associated with elevated temperatures, highlighting its significance in contributing to the UHI effect in Bologna. These consistent findings across GIS, correlation, and regression analyses contribute to a better understanding of the intricate relationship between urban morphology and microclimate. The study's insights provide valuable information that can be utilized for urban planning, offering potential strategies to address and mitigate the UHI effect.