Factors Controlling the Variability of Photolysis Rates of NO2 and O1D in the Complex Environment of the Eastern Mediterranean
Time series of photolysis rates of ozone (JO1D) and nitrogen dioxide (JNO2), for the period 2002–2006, at the remote coastal Finokalia station on Crete Island (25°60′E, 35°24′N), were used in order to investigate the factors that control their levels and their temporal characteristics. The study focuses on the main climatological aspects of the photolysis rates and investigation of the factors that control their variability, with emphasis on the quantification of aerosol and total ozone effects. The average Aerosol Optical Depth in the area which equals to 0.27 ± 0.13, leads to percentage reduction of JNO2 in the range 5–14% at 60° solar zenith angle (sza). For typical ozone column content (300–315 DU) the respective range of reduction for JO1D is 8–24%. Overall, at regional AOD background levels (~0.1) the percentage reduction of both JNO2 and JO1D is lower than 6%, in the range of sza 15–75°. Dust is shown to be 1.5 times more efficient absorber than average aerosol types in the area. During high aerosol loads (AOD 0.5–0.7) the percentage reduction of Js can raise to 40% for high sza.
KeywordsAerosol Optical Depth Total Ozone Solar Zenith Angle Tropospheric Ozone Dust Aerosol
This work has been conducted within the framework of CIRCE project (Climate Change and Impact Research: the Mediterranean Environment), funded by the Commission of the European Union (Contract No 036961 GOCE), http://www.circeproject.eu/.
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