The urban heat island of the Metropolitan City of Turin. Strategies for a sustainable urban planning

Globally, the world population living in cities is increasing and then the sustainability and liveability of urban spaces are rising the attention of the scientific community mainly in term of warming increase and health risk. In this work, the microclimate of outdoor spaces is investigated considering the different outdoor air temperatures registered by various weather stations in the city of Turin (Italy) and its surroundings with 12 municipalities. The air temperature variations are correlated with the built urban morphology, the solar exposure of urban spaces, the albedo coefficients of outdoor surfaces and other variables as the percentage of vegetation and water, the distance from the town centre and the Land Surface Temperature. With a multiple linear regression analysis the air temperatures have been correlated with the urban variables to obtain a simple model for the prediction of the average monthly air temperature in the Metropolitan City of Turin. This model can be used to understand the different microclimates within Turin and between the urban and the rural areas, and to evaluate the most influential variables on the air temperature variations. The resulted models could help urban planners to predict the microclimate in new districts, but also in the existent ones, as a function of the urban form and of the outdoor materials chosen to mitigate the UHI phenomenon.