A Circulation Weather Type Analysis of Urban Effects on Daily Thermal Range for Milan (Italy)

Abstract

We present a first attempt to analyse the effect of a large urban park (Parco Nord Milano—PNM) on the Urban Heat Island (UHI) of the city area of Milan. Specifically, analysis of the effect of three cyclonic and three anticyclonic circulation weather types (CWTs) on the frequency distribution of the daily thermal range (DTR) of five weather stations in Milan shows the stabilizing effect of the city on the DTR when compared with suburban and rural areas, generating a modal class of 4 °C in winter and 9 °C in summer. In parallel, a temperature transect of the urban park Parco Nord Milano was performed by bicycle during a day of anticyclonic summer weather in order to understand the effect of the park on the UHI. This investigation highlighted the homogenization effect on temperatures induced by the thermal turbulence triggered by intense sunshine.