Regional levels of ozone in the troposphere over eastern Mediterranean

Kourtidis, K.; Zerefos, C. S.; Rapsomanikis, S.; Simeonov, V.; Balis, D.; Perros, P.; Thompson, A. M.; Witte, J. C.; Calpini, B.; Sharobiem, W. M.; Papayannis, A.; Mihalopoulos, N.; Drakou, R.

doi:10.1029/2000jd000140

Cited by 93 publications

(60 citation statements)

References 35 publications

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“…Similar results were obtained during short-term intensive measuring campaigns over the Aegean Sea (MEDCAPHOT-TRACE campaign in summer 1994, PAUR I campaign in summer 1996, PAUR II campaign in summer 1999, MINOS campaign in summer 2001) using aircraft and surface measurements PAUR report, 1998;Kourtidis et al, 2002;Kouvarakis et al, 2002;Traub et al, 2003;Roelofs et al, 2003). Recent continuous 3-year (1997-1999) measurements in the island of Crete agree also with the measurements presented above (Kouvarakis et al, 2000).…”

Section: Discussionsupporting

confidence: 84%

“…High surface ozone values have been already reported at western and central Mediterranean sites in Italy and Spain (Millan et al, 1992;Bonasoni et al, 2000). Concerning the eastern Mediterranean, several intensive shortterm measurements including aircraft flights have been carried out in Greece, around the urban area of Athens and over the Aegean Sea during the past decade, which recorded high surface ozone values (Kallos, 1995;Ziomas, 1998;PAUR report, 1998;Kourtidis et al, 2002;Kouvarakis et al, 2002;Traub et al, 2003;Roelofs et al, 2003). In Greece, few systematic rural ozone measurements outside the greater Athens area have been published so far covering time-periods of several months to 2-3 years (Kourtidis et al, 1996;Glavas, 1999;Kouvarakis et al, 2000).…”

Section: Introductionmentioning

confidence: 95%

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A climatological study of rural surface ozone in central Greece

Kalabokas

Repapis

2004

Atmos. Chem. Phys.

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Abstract. Recent studies show that surface ozone levels at rural sites in Greece are generally high when compared with rural ozone measurements at northern European sites. The area of SE Europe, including Greece, is not very well monitored regarding rural ozone in comparison to central and northern Europe. In order to have the best possible picture of the rural surface ozone climatology in the area, based on the available data-sets of long-term continuous monitoring stations, the 10-year measurement records (1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996) of the Athens peripheral station of Liossia, (12 km N of the city center) and the urban background station of Geoponiki (3 km W) as well as the 4-year record (1996)(1997)(1998)(1999) of the rural station of Aliartos (100 km NW of Athens), are analyzed in this paper. The data for Liossia and Geoponiki stations are screened for cases of strong airflow from rural areas (N-NE winds stronger than 5 m/s). The variation characteristics of the average rural ozone afternoon levels (12:00-18:00), with the best vertical atmospheric mixing, are mainly examined since these measurements are expected to be representative of the broader area. In all three stations there is a characteristic seasonal variation of rural ozone concentrations with lowest winter afternoon values at about 50 µg/m 3 in December-January and average summer afternoon values at about 120 µg/m 3 in July-August, indicating that high summer values are observed all over the area. The rural summer afternoon ozone values are very well correlated between the three stations, implying spatial homogeneity all over the area but also temporal homogeneity, since during the 13-year period 1987-1999 the rural afternoon ozone levels remained almost constant around the value of 120 µg/m 3 .

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Section: Discussionsupporting

confidence: 84%

Section: Introductionmentioning

confidence: 95%

A climatological study of rural surface ozone in central Greece

Kalabokas

Repapis

2004

Atmos. Chem. Phys.

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“…Varotsos et al, 1993;Kalabokas et al, 2000;Kourtidis et al, 2002;Kouvarakis et al, 2002;Zerefos et al, 2002;Lelieveld et al, 2002;Roelofs et al, 2003;Kalabokas and Repapis, 2004). Such high summer levels are a general characteristic of the ozone vertical profiles in the region.…”

Section: Introductionmentioning

confidence: 93%

Examination of the atmospheric conditions associated with high and low summer ozone levels in the lower troposphere over the eastern Mediterranean

et al. 2013

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Abstract. In order to evaluate the observed high rural ozone levels in the eastern Mediterranean area during summertime, vertical profiles of ozone measured in the period [1994][1995][1996][1997][1998][1999][2000][2001][2002][2003][2004][2005][2006][2007][2008] in the framework of the MOZAIC project (Measurement of Ozone and Water Vapor by Airbus in Service Aircraft) over the eastern Mediterranean basin (Cairo, Tel Aviv, Heraklion, Rhodes, Antalya) were analyzed, focusing in the lower troposphere (1.5-5 km). At first, vertical profiles collected during extreme days with very high or very low tropospheric ozone mixing ratios have been examined together with the corresponding back-trajectories. Also, the average profiles of ozone, relative humidity, carbon monoxide, temperature gradient and wind speed corresponding to the 7 % highest and the 7 % lowest ozone mixing ratios for the 1500-5000 m height layer for Cairo and Tel Aviv have been examined and the corresponding composite maps of geopotential heights at 850 hPa have been plotted. Based on the above analysis, it turns out that the lower-tropospheric ozone variability over the eastern Mediterranean area is controlled mainly by the synoptic meteorological conditions, combined with local topographical and meteorological features. In particular, the highest ozone concentrations in the lower troposphere and subsequently in the boundary layer are associated with largescale subsidence of ozone-rich air masses from the upper troposphere under anticyclonic conditions while the lowest ozone concentrations are associated with low pressure conditions inducing uplifting of boundary-layer air, poor in ozone and rich in relative humidity, to the lower troposphere.

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“…They identified transport from the European continent as the main mechanism controlling the O 3 levels in the EM, especially during summer when O 3 reaches a July maximum of 58 ± 10 ppbv. Moreover, on a larger regional scale, Kourtidis et al (2002) used ozonesonde ascents, lidar observations, ship cruises, and aircraft flights to show that south and southwestern synoptic flows associated with Saharan dust events result in lower O 3 above the planetary boundary layer by 20-35 ppbv, as compared to northerly flows, which transport air from continental Europe. Based on 16 years of O 3 concentrations measured at the EMEP Agia Marina Xyliatou rural background station in Cyprus and three other remote marine sites over the western, central, and eastern parts of the island, Kleanthous et al (2014) have shown that local precursors contribute to only about 6 % (∼ 3 ppbv) of the observed O 3 .…”

Section: Processes Controlling O 3 Formationmentioning

confidence: 99%

Atmospheric pollution over the eastern Mediterranean during summer – a review

et al. 2017

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Abstract. The eastern Mediterranean (EM) is one of the regions in the world where elevated concentrations of primary and secondary gaseous air pollutants have been reported frequently, mainly in summer. This review discusses published studies of the atmospheric dispersion and transport conditions characterizing this region during the summer, followed by a description of some essential studies dealing with the corresponding concentrations of air pollutants such as ozone, carbon monoxide, total reactive nitrogen, methane, and sulfate aerosols observed there.The interlaced relationship between the downward motion of the subsiding air aloft induced by global circulation systems affecting the EM and the depth of the Persian Trough, a low-pressure trough that extends from the Asian monsoon at the surface controlling the spatiotemporal distribution of the mixed boundary layer during summer, is discussed. The strength of the wind flow within the mixed layer and its depth affect much the amount of pollutants transported and determine the potential of the atmosphere to disperse contaminants off their origins in the EM. The reduced mixed layer and the accompanying weak westerlies, characterizing the summer in this region, led to reduced ventilation rates, preventing an effective dilution of the contaminants. Several studies pointing at specific local (e.g., ventilation rates) and regional peculiarities (long-range transport) enhancing the build-up of air pollutant concentrations are presented.Tropospheric ozone (O 3 ) concentrations observed in the summer over the EM are among the highest over the Northern Hemisphere. The three essential processes controlling its formation (i.e., long-range transport of polluted air masses, dynamic subsidence at mid-tropospheric levels, and stratosphere-to-troposphere exchange) are reviewed. Airborne campaigns and satellite-borne initiatives have indicated that the concentration values of reactive nitrogen identified as precursors in the formation of O 3 over the EM were found to be 2 to 10 times higher than in the hemispheric background troposphere. Several factors favor sulfate particulate abundance over the EM. Models, aircraft measurements, and satellite-derived data have clearly shown that sulfate has a maximum during spring and summer over the EM. The carbon monoxide (CO) seasonal cycle, as obtained from global background monitoring sites in the EM, is mostly controlled by the tropospheric concentration of the hydroxyl radical (OH) and therefore demonstrates high concentrations over winter months and the lowest concentrations during summer when photochemistry is active. Modeling studies have shown that the diurnal variations in CO concentration during the summer result from long-range CO transport from European anthropogenic sources, contributing 60 to 80 % of the boundary-layer CO over the EM. The values retrieved from satellite data enable us to derive the spatial distribution of methane (CH 4 ), identifying August as the month with the highest levels over the EM. The outcomes of a...

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Regional levels of ozone in the troposphere over eastern Mediterranean

Cited by 93 publications

References 35 publications

A climatological study of rural surface ozone in central Greece

A climatological study of rural surface ozone in central Greece

Examination of the atmospheric conditions associated with high and low summer ozone levels in the lower troposphere over the eastern Mediterranean

Atmospheric pollution over the eastern Mediterranean during summer – a review

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