Current Urban Thermal Characteristics and Future Projections in the Mediterranean Basin: Case Studies From Guimares, Portugal, and Turin, Italy Using Remote Sensing and the SUEWS Model

Southern European cities face increasing challenges from urban overheating and evolving climate hazards such as heatwaves and droughts. Vegetated parks can mitigate urban climate impacts, providing significant relief. This study, part of the EU Horizon project DISTENDER, assesses the urban heat island (UHI) effect and intra-urban thermal variations for Guimares, Portugal, and Turin, Italy. First, thermal patterns and the cooling effects of green spaces during typical summer conditions and extreme heat and drought events were derived using remotely-sensed Land Surface Temperatures (LST) from Landsat 8/9 and MODIS Aqua/Terra satellites. Next, multi-year (1981 2049) high-resolution urban simulations, were conducted using the Surface Urban Energy and Water Balance Scheme (SUEWS). These simulations were forced with statistically downscaled data from three climate models (CanESM5, EC-EARTH3, MPI-ESM1-2-HR) under four shared socioeconomic pathways (SSPs 1-2.6, 2-4.5, 3-7.0, 5-8.5). Results indicate that city centres are up to 4 C hotter than surrounding natural areas. While UHI intensity is projected to remain relatively stable throughout the years, air temperatures are expected to rise by approximately 2.0 C for Guimares and 1.6 C for Turin under the high emission scenario by the 2050s. These findings underscore the need for urban planning strategies to mitigate future heat risks in Southern European cities.