Vertical ozone measurements in the troposphere over the Eastern Mediterranean and comparison with Central Europe

[摘要] Vertical ozone profiles measured in the period 1996–2002 in the framework ofthe MOZAIC project (Measurement of Ozone and Water Vapor by Airbus inService Aircraft) for flights connecting Central Europe to the EasternMediterranean basin (Heraklion, Rhodes, Antalya) were analysed in order toevaluate the high rural ozone levels recorded in the Mediterranean areaduring summertime. The 77 flights during summer (JJAS) showed substantially(10–12 ppb, 20–40%) enhanced ozone mixing ratios in the lower troposphereover the Eastern Mediterranean frequently exceeding the 60 ppb, 8-h EUair quality standard, whereas ozone between 700 hPa and 400 hPa was onlyslightly (3–5 ppb, 5–10%) higher than over Central Europe. Analysis ofcomposite weather maps for the high and low ozone cases, as well asback-trajectories and vertical profiles of carbon monoxide, suggest that themain factor leading to high tropospheric ozone values in the area isanticyclonic influence, in combination with a persistent northerly flow inthe lower troposphere during summertime over the Aegean. On the other handthe lowest ozone levels are associated with low-pressure systems, especiallythe extension of the Middle East low over the Eastern Mediterranean area.

[学科分类] 大气科学