FOG EVENT CLIMATOLOGY FOR ZAGREB AIRPORT

Sa？etak This work presents a comprehensive study of climatology of fog events at Zagreb Airport. The data used in the study consists of observations from 1994 to 2015, in form of METAR reports. Fog events are classified into five types based on the physical mechanism of formation. The results show a decrease in the annual number of fog events at Zagreb Airport during the last 22 years. Fog is more frequent in the period between September and February, which can be designated as fog season. During spring and summer fog is a relatively rare phenomenon. Fog is usually quite dense; events with a minimum visibility of over 200 m occurred in only 29% of cases. Radiation fog is the dominant type of fog. The analysis has also shown that advective fog is very rare during summer, while precipitation fog and cloud base lowering fog occur only during fall and winter. All fog types except evaporation fog have a similar distribution of duration. Radiation fog and advective fog are the densest types; precipitation fog is the least dense type. A closer analysis of radiation fog has provided data on the annual/diurnal distribution of frequencies of onset and dissipation, wind during onset or dissipation, and persistence