Assessing the Impact of Urban Morphology on Urban Heat Island Intensity in Beirut: A Temporal Comparative Approach (2010–2021)

Abstract

Urban densification in rapidly growing Mediterranean cities raises major challenges in terms of thermal comfort and microclimate regulation. This study explores the impact of morphological transformations on local air temperatures in the residential neighborhood of Furn Hayek in Beirut between 2010 and 2021.
Using the ENVI-met software, it was possible to simulate temperatures at the microclimatic scale. Through mapping and data from the Sky View Factor (SVF), as well as modeled temperature values at five study points (R2, R4, R5, R7, R9), the influence of building height, SVF, and urban canyon geometry on hourly air temperatures was assessed.
During the study period, the average building height increased from 19 to 28 meters, while the number of buildings decreased by 34% due to redevelopment projects. These changes had a limited effect on average daytime temperature (variation < 0.5 °C), but significantly impacted local microclimatic conditions: the drop in SVF values in certain areas between 2010 and 2021 led to thermal differences of up to 2.5 °C, especially around midday.
The results highlight the critical role of sky visibility and street orientation in local thermal regulation. It is recommended that urban planning policies in Beirut incorporate climate-sensitive morphological indicators into zoning regulations to optimize the microclimatic performance of densely built neighborhoods.