Regional levels of ozone in the troposphere over eastern Mediterranean

During the last 5 years, information on the regional tropospheric ozone levels over the eastern Mediterranean has become available but was confined to measurements at ground level. Here available information is expanded with measurements at two more rural ground level sites spanning 8° latitude, ozonesonde ascents, lidar observations, ship cruises, and aircraft flights. During wintertime the ozone monthly values are 10-20 ppbv higher than values at other European sites, while during summertime the values are comparable. This results in regional ozone background levels in the area that are above the European Union (EU) 32 ppb/24 hours phytotoxicity limit during the entire year. Late spring lidar observations show that south and southwestern synoptic flows which are associated with Saharan dust events result in lower ozone above the planetary boundary layer (PBL) by 20-35 ppbv as compared to these during northerly flows, which transport air from continental Europe. These lidar observations along with ship measurements during July show that ozone is enhanced 1.5-2.2 times in the continental outflow, when compared to aged maritime air or air from the African continent. These results along with ozonesonde observations suggest that ozone abatement in the area is largely beyond the control of regional emissions and can be controlled only with emission reductions on a European scale. During September, measured background NO and NO 2 levels between 3 and 4.5 km above sea level ranged from 1 to 221 pptv and from 102 to 580 pptv, respectively. The troposphere contains around 40-70 Dobson units of ozone during summer and around 20-30 Dobson units during winter.

[1]  Christos Zerefos,et al.  Photochemical Activity and Solar Ultraviolet Radiation (PAUR) Modulation Factors: An overview of the project , 2002 .

[2]  Christos Zerefos,et al.  Spatial and temporal variability of tropospheric ozone (O3) in the boundary layer above the Aegean Sea (eastern Mediterranean) , 2002 .

[3]  C. Zerefos,et al.  A case study on the possible link between surface ozone photochemistry and total ozone column during the PAUR II experiment at Crete: Comparison of observations with box model calculations , 2002 .

[4]  B. Gimeno,et al.  Evidence of ozone-induced adverse effects on crops in the Mediterranean region , 2001 .

[5]  Jostein K. Sundet,et al.  Model calculations of present and future levels of ozone and ozone precursors with a global and a regional model , 2001 .

[6]  R. Losno,et al.  Ozone Production Efficiency in Savanna and Forested Areas during the EXPRESSO Experiment , 2001 .

[7]  B. Doddridge,et al.  A tropical Atlantic Paradox: Shipboard and satellite views of a tropospheric ozone maximum and wave‐one in January–February 1999 , 2000 .

[8]  T. Berntsen,et al.  Chemical effects of UV fluctuations inferred from total ozone and tropospheric aerosol variations , 2000 .

[9]  Kostas Tsigaridis,et al.  Temporal variations of surface regional background ozone over Crete Island in the southeast Mediterranean , 2000 .

[10]  Overview of Concepts and Results of the Paur I and Paur II Projects , 2000 .

[11]  J. Bartzis,et al.  Mediterranean rural ozone characteristics around the urban area of Athens , 2000 .

[12]  Paul S. Monks,et al.  A review of the observations and origins of the spring ozone maximum. , 2000 .

[13]  S. Glavas.  Surface ozone and NOx concentrations at a high altitude Mediterranean site, Greece , 1999 .

[14]  F. Santis.  New directions: will a new European vegetation ozone standard be fair to all European Countries?☆ , 1999 .

[15]  Valentin Simeonov,et al.  UV ozone DIAL based on a Raman cell filled with two Raman active gases , 1999, Industrial Lasers and Inspection.

[16]  H van den Bergh,et al.  Influence of the photomultiplier tube spatial uniformity on lidar signals. , 1999, Applied optics.

[17]  B. Katsoulis.  The potential for long-range transport of air-pollutants into Greece: a climatological analysis. , 1999, The Science of the total environment.

[18]  V. Simeonov,et al.  Planetary Boundary Layer ozone fluxes from combined airborne, ground based lidars and Wind profilers measurements , 1999 .

[19]  J. Lelieveld,et al.  Tropospheric ozone and related processes , 1999 .

[20]  The behaviour of ozone and peroxyacetyl nitrate concentrations for different wind regimes during the MEDCAPHOT-TRACE campaign in the greater area of Athens, Greece , 1998 .

[21]  V. Kotroni,et al.  On the Long‐Range transport of air pollutants from Europe to Africa , 1998 .

[22]  R. Draxler.  An Overview of the HYSPLIT_4 Modelling System for Trajectories, Dispersion, and Deposition , 1998 .

[23]  J. Seinfeld,et al.  Atmospheric Chemistry and Physics: From Air Pollution to Climate Change , 1998 .

[24]  B. Gomišček,et al.  On the Spatial Distribution and Seasonal Variation of Lower-Troposphere Ozone over Europe , 1997 .

[25]  V. Simeonov,et al.  Ozone LIDAR as an Analytical Tool in Effective Air Pollution Management: The Geneva 96 Campaign , 1997, CHIMIA.

[26]  Jos Lelieveld,et al.  A three-dimensional chemistry/general circulation model simulation of anthropogenically derived ozone in the troposphere and its radiative climate forcing , 1997 .

[27]  G. Ancellet,et al.  Evidence for changes in the ozone concentrations in the free troposphere over southern france from 1976 to 1995 , 1997 .

[28]  W. Junkermann,et al.  Diurnal fluctuations of secondary photooxidants in air and of detoxification systems in the foliage of Mediterranean forest trees , 1997 .

[29]  J. Fishman,et al.  NASA GTE TRACE A experiment (September–October 1992): Overview , 1996 .

[30]  D. Hauglustaine,et al.  Radiative forcing due to increased tropospheric ozone concentrations , 1996 .

[31]  Jennifer A. Logan,et al.  Trends in the vertical distribution of ozone: An analysis of ozonesonde data , 1994 .

[32]  G. Mégie,et al.  Intercomparison campaign of vertical ozone profiles including electrochemical sondes of ECC and Brewer-Mast type and a ground based UV-differential absorption lidar , 1994 .

[33]  B. Anderson,et al.  The impact of U. S. continental outflow on ozone and aerosol distributions over the western Atlantic , 1993 .

[34]  J. Weber,et al.  Analysis of the relationships among O(3) uptake, conductance, and photosynthesis in needles of Pinus ponderosa. , 1993, Tree physiology.

[35]  P. Matrai,et al.  Low-level atmospheric sulfur dioxide measurement using HPLC/fluorescence detection , 1993 .

[36]  I. Nouchi.  Changes in antioxidant levels and activities of related enzymes in rice leaves exposed to ozone , 1993 .

[37]  Andreas Volz,et al.  Evaluation of the Montsouris series of ozone measurements made in the nineteenth century , 1988, Nature.