Cooling effect of an urban green area in the city centre of Florence, Italy

In these last decades the rapid increase of cities dimension and density has caused an intensification of the Urban Heat Island (UHI) effect that is the thermal difference between the centre of an urban area and the rural surroundings. UHI effect in Florence is particularly high during Summer when air temperature reaches values that can affect health and quality of life of people. Green areas can play an important role in the mitigation of UHI. The aim of this work is to evaluate the thermal effect and particularly the mitigating effect of an urban green area on the air temperature regimes during Summer in the centre of the city of Florence. This study was carried out using data collected since 2005 by a sensor set in the Botanic Garden of Florence, that is located in the old core of the city and is surrounded by buildings, and another sensor set in a built-up area of the city centre. Several thermal indices were calculated and daily and monthly differences between the two sites were analysed. Our results confirm the important cooling role of green areas in the urban context and its effects on plant phenology and energy consumption. This study suggests that thermal indices can be effectively used by the urban planners to design more liveable urban spaces.