Environmental factors affecting fog formation

Abstract

Fog is an important phenomenon related to both atmospheric physics and chemistry, and has a significant impact on our environment. Although the meteorological factors relevant to fog formation have been extensively studied, other factors remain unexplored. Here we summarise our recent results from several studies (Hůnová et al., 2018, 2021 a, 2021 b, 2022), where we examined observed and measured long-term data from the Czech Republic (1989–2015) and Romania (1981–2017). Our focus was on the environmental factors that drive fog formation. Specifically, we examined the effects of terrain, water and forests (for Romania), and ambient air pollution (for the Czech Republic). The long-term empirical data were analysed using advanced statistical modelling GAM (generalised additive model). In terms of terrain, apart from altitude, slope and landform appeared to have a strong influence on fog formation. Forests have a significant effect on fog formation, the most significant being the forest area within 3 km of the the fog observation point, with coniferous and broad leave trees having different effects. Not surprisingly, the presence of water body in the vicinity of a fog site affects fog formation, but less so than altitude or seasonality. Freshwater and seawater show clear differences in both the seasonal profile and frequency of fog. Ambient air pollution, indicated by the daily mean concentrations of sulphur dioxide and nitrogen oxides, was the most important explanatory variable (apart from relative humidity) in modelling the probability of fog at three Centre European sites reflecting different environments (urban, rural and mountain).