Diurnal patterns and drivers of urban fog dissipation in Milan

The goal of this project is to detect and analyze local and large-scale drivers of urban fog dissipation using satellite data. 

In urban areas the heat island effect is often associated with a suppression or an accelerated dissipation of fog. This can be explained by night-time urban warming that lifts the cloud base, while day-time solar radiation may contribute to fog ”burnoff” in the morning hours due to enhanced heating of the surface and the air above. However, the processes determining the urban fog life cycle are not yet fully understood. To better understand determinants of fog life cycle in urban areas, meteorological conditions associated with urban fog dissipation are analyzed in Milan using a variety of data sources. 

SEVIRI (Spinning Enhanced Visible Infra-Red Imager) satellite data is used to determine urban fog persistence and dissipation, while meteorological data from METAR observations (Meteorological Aerodrome Report), urban weather stations and ERA-5 reanalysis is used to investigate its local and large-scale characteristics.. Distinct meteorological patterns are identified that favor fog dissipation in Milan on particular days and the preceding nights. This study has implications for the urban climate in many European cities where morning fog variability is determining the urban radiation budget and, consequently, heat stress in urban environments.