Analysis of urban heat island and human thermal comfort in a Mediterranean city: A case study of Lecce (Italy)

Abstract

A Mediterranean city was studied to examine the Urban Heat Island (UHI), with near-surface temperature measurements at five locations in both urban and suburban areas over a nine-year period from 2013 to 2021. The study aims to analyse the intensity of UHI and evaluate urbanisation effects on human thermal comfort also considering the effect of heat waves. The UHI study indicated that the intensity of the phenomenon peaked at night (ranging from 1.1 to 1.6 °C) in the city's core, while its impact was comparatively weaker during the central hours of the day. The diurnal peak of the UHI intensity was between 1–3 °C, but in unfavourable conditions, it exceeded 5–6 °C. The intensity and daily maximum of UHI decreased when the wind speed from north exceeded 3 m s−1. Thermal comfort analysis indicated the worst conditions in August, with high discomfort and heat stress risk during the early afternoon. The analysis shows a significant deterioration of thermal comfort over the investigated period. Results achieved with this work point out the importance of implementing measures to mitigate thermal discomfort, particularly when temperatures are already high and exacerbated by the UHI effect.