Comparative assessment of Urban Heat Island Intensity in Bari (Italy) and in 5 major European cities

e Urban Heat Island (UHI) is an alarming phenomenon regarding the presence of higher air tem- peratures in urban districts compared with the surrounding rural area. Indeed, the UHI is becoming increasingly serious for the built environment specially in combination with warming climate, ex- tensive urbanization, and aging population. To this aim, recent researches calibrated quantitative indexes to forecast the maximum UHI intensity in urban districts by exploiting a holistic multicriteria approach and open source data. Such novel tools open up the possibility to investigate the UHI in- tensity in numerous districts, make useful comparisons among cities and identify the best mitigation strategies for the future. This paper proposes for the first time the evaluation of the absolute max UHI intensity of the 17 urban districts of Bari, Puglia (Italy) by exploiting a recent multi-criteria index-based approach. In addition, the districts of Bari are compared with other urban district of 5 European cities (Madrid, Paris, Berlin, Milan and London). The comparison allows to emphasize the positive and negative aspects of the Apulian city and define useful mitigation strategies. In particular, as a result, four different mitigation scenarios have been obtained in the “Murattiano” district by improving the Albedo and including a 10%, 15% and 30% of greenery to reduce the UHII from 6.71 °C to 6,44 °C, 6,18 °C and 5,03° re- spectively. The research required extensive data acquisition and analysis in order to investigate and compare a total of 335 urban districts of 6 European cities: 17 district in Bari (Italia); 21 in Madrid (Spain); 80 in Paris (France); 96 in Berlin (Germany); 88 in Milan (Italy) and 33 in London (UK).