Natural Hazards and Earth System Science www.nat-hazards-earth-syst-sci.net 1561-8633 1684-9981 9 5 2009 10.5194/nhess-9-1541-2009 http://www.nat-hazards-earth-syst-sci.net/9/1541/2009/ http://www.nat-hazards-earth-syst-sci.net/9/1541/2009/nhess-9-1541-2009.html http://www.nat-hazards-earth-syst-sci.net/9/1541/2009/nhess-9-1541-2009.pdf 1541 1549 2009-09-03 Fog characteristics at the airport of Thessaloniki, Greece S. N. Stolaki sstolaki@geo.auth.gr S. A. Kazadzis D. V. Foris Th. S. Karacostas Department of Meteorology and Climatology, School of Geology, A.U.Th., Greece Finnish Meteorological Institute, Climate Change Unit, Finland National Observatory of Athens, Institute for Environmental Research and Sustainable Development, Greece Meteorological Applications Center, Greek Agricultural Insurance Organization, Greece A statistical approach in order to study fog event characteristics occuring at the airport of Thessaloniki, Northern Greece is presented in this work. To achieve this, the seasonal and diurnal characteristics of fog are investigated using 35 years (1971–2005) of observations of meteorological parameters such as: visibility, air temperature, dew point temperature, air relative humidity, wind vector, precipitation, and cloud base height and coverage. Hourly surface observations of fifteen (15) years (1991–2005) are used to identify fog events induced by various physical mechanisms. Fog events are classified into fog types through the application of objective criteria that are derived upon fog formation processes and under the influence of various physiographic features. The temporal variability of different fog type occurrences are examined and the events are characterized according to their duration and intensity. <br><br> The results are somehow affected by regional and local factors. Fog is mainly formed in winter time (~64%) with an enhanced likelihood to appear also in late autumn (19%). 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