On the atmospheric circulation characteristics associated with fog in Ioannina, north‐western Greece

Abstract

The evolution of the atmospheric circulation over Europe and the Mediterranean during fog events in Ioannina, north-western Greece, is examined for the period 1957-2002. A 24-h period starting at 12 : 00 UTC is defined as a fog day, when at least one of the present and/or past weather codes of the corresponding SYNOPs refers to fog. A sequence of such fog days is defined as a fog event. In total, 1019 fog events are found during the period under study. A methodology scheme using S-mode factor analysis and K-means cluster analysis is applied to the patterns of 850 hPa air temperature and 1000 and 500 hPa geopotential heights for the day before the initiation, the first day of occurrence and the day after the dissipation of fog, resulting in the classification of the 1019 fog events into ten clusters. For each one of the ten clusters, the mean 00 : 00 UTC patterns of the above parameters are constructed for 3 days. These patterns correspond to the evolution of the atmospheric circulation associated with fog formation and dissipation in the Ioannina region. Most of the patterns are characterized by anticyclonic activity or a weak southerly flow over Greece. The differences among the ten clusters refer mainly to the position and the intensity of the surface and upper air synoptic systems involved.

Carbonaceous Aerosols in Contrasting Atmospheric Environments in Greek Cities: Evaluation of the EC-tracer Methods for Secondary Organic Carbon Estimation

“…Ioannina is a city in the northwest part of Greece, lying on a plateau at an elevation of about 500 m and surrounded by mountains (≈1800-2400 m). The city is next to the Pamvotis lake ( Figure 1), and is characterized by frequent fog during wintertime, due to increased relative humidity, weak winds and basin-like characteristics, whereas the mean winter temperature is ≈6-9 • C [43]. Notwithstanding the low temperatures, which lead to excessive RWB and humid conditions and, therefore, to the appearance of intense smog events, particle pollution in Ioannina has been minimally documented [44].…”

Atmospheric conditions controlling extreme summertime evapotranspiration in Poland (central Europe)

“…However, all of these individual meteorological and hydrometeorological parameters, including evapotranspiration, are affected by atmospheric circulation, i.e., the large-scale movement of air masses in the atmosphere. The impact of atmospheric circulation on different meteorological elements has been thoroughly studied in relation to, for example, air temperature (Xoplaki et al 2003), precipitation (Jacobeit et al 2009), fog (Houssos et al 2012), snow cover and melt (Bednorz 2011), and hail (Suwała 2013). However, information about the influence of atmospheric circulation on pan evaporation and evapotranspiration remains scarce (Jalili et al 2012).…”

A spatially explicit and temporally highly resolved analysis of variations in fog occurrence over Europe

“…Wanner, ; Houssos et al . ; Łupikasza and Niedźwiedź, ), even if local micrometeorological influences are found to be additional contributors to fog formation and dissipation processes here.…”

“…The basic fog-promoting properties of anticyclonic weather conditions in the lowlands, in contrast to cyclonic weather conditions, are also emphasized in field studies based on station data (e.g. Wanner, 1979;Houssos et al, 2012;Łupikasza and Niedźwiedź, 2016), even if local micrometeorological influences are found to be additional contributors to fog formation and dissipation processes here.…”