Urban Heat Island Monitoring Using Thermal Infrared Satellite Data in Italian cities

Abstract. Climate change is driving a sustained increase in global temperatures and an intensification of extreme events, including heatwaves. Urban areas are typically warmer than the surrounding suburban and rural environments, a phenomenon known as the Urban Heat Island (UHI) due to the presence of buildings and inhomogeneous surfaces, which affects surface energy and water exchanges as well as the local meteorology. UHI strongly affect urban climate, ecosystems, air quality, and human thermal comfort, and its impact is exacerbated during heatwaves, with risks for human health. Monitoring and characterizing UHI is crucial for urban planning, climate mitigation and adaptation strategies. The Surface Urban Heat Island (SUHI) can be effectively investigated through the study of the Land Surface Temperature (LST) derived from satellite observations, enabling comprehensive spatial and temporal analyses of urban thermal patterns, including the identification of hot- and cold-spots, and the assessment of mitigation strategies.

In this study, thermal infrared satellite observations of LST are used to characterize the SUHI and its dynamics over selected urban areas in Italy. A decadal dataset is built using Landsat 8 data to analyse long-term evolution. For recent years, Landsat 8 data are combined with ECOSTRESS data, significantly enhancing temporal sampling. This multi-sensor approach enables an improved assessment of urban temperature evolution and its response to climate change.