Photosmog episodes in the central Mediterranean

Abstract

Photosmog episodes are the origin of events of high ozone mixing ratios, greater than 80ppb, which were analysed using the NOAA (National Oceanic and Atmospheric Administration) Hysplit 4 model and the Flextra at NILU (Norsk Institutt for Luftforskning) model to calculate back trajectories for these high ozone mixing ratios events. These were also studied in detail by analysing wind measurement data and other meteorological data recorded and collected at Giordan lighthouse, which is located on the island of Gozo, midway between Southern Europe and North Africa. Six of these events between 1997 and 2006 were discussed in detail in this thesis. These six events include episodes where ozone was formed and arrived from the northwest direction that is from Sicily, where ozone was not formed and arrived from the southeast direction that is from Malta (this was recorded as a negative peak) and where ozone was not formed but arrived from the northwesterly direction, which was also recorded as a negative peak at Giordan lighthouse.