Urban Heat Island and Future Projections: A Study in Thessaloniki, Greece

Future climate simulations have been produced for three 5-year periods until the end of twenty-first century using the WRF-ARW numerical weather prediction model for the greater area of Thessaloniki in the framework of the forecasting System for urban heaT Island effect (LIFE-ASTI) programme. In the present study, we analyse the characteristics of heat wave days in present and future at a central urban region of Thessaloniki and a rural region around the city in order to investigate the urban heat island effect under extreme heat. The number of heat wave days until 2100 is expected to increase by >12 times more than in the present. It is notable that more than 60% of the heat wave days within the urban area will be characterized by minimum temperatures ≥30 °C, while this percentage will be ~12% for the rural area. Finally, while in the present the urban heat island intensity during heat wave days presents mostly values 1–3 °C, in the future the intensity will be larger, in a few cases exceeding even 6 °C.