Temporal variations of surface regional background ozone over Crete Island in the southeast Mediterranean

Kouvarakis, G.; Tsigaridis, Kostas; Kanakidou, Maria; Mihalopoulos, Nikos

doi:10.1029/1999jd900984

Cited by 177 publications

(158 citation statements)

References 25 publications

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“…The eastern Mediterranean atmospheric O 3 concentrations are characterized by seasonal variability with the maxima observed during the summer (Kouvarakis et al, 2000;Gerasopoulos et al, 2005;Kalabokas et al, 2008;Kleanthous et al, 2014) due to intense photochemical activity and the prevailing meteorological conditions. The collocation of the south-eastern Europe/Balkan Peninsula high-pressure system and the Asian monsoon low-pressure regime to the east causes northerly circulation over the Aegean Sea that sheers to north-westerly over the eastern Mediterranean (Tyrlis et al, 2013;Anagnostopoulou et al, 2014).…”

Section: G K Georgiou Et Al: Summer Eastern Mediterranean Air Qualmentioning

confidence: 99%

Air quality modelling in the summer over the eastern Mediterranean using WRF-Chem: chemistry and aerosol mechanism intercomparison

et al. 2018

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Abstract. We employ the WRF-Chem model to study summertime air pollution, the intense photochemical activity and their impact on air quality over the eastern Mediterranean. We utilize three nested domains with horizontal resolutions of 80, 16 and 4 km, with the finest grid focusing on the island of Cyprus, where the CYPHEX campaign took place in July 2014. Anthropogenic emissions are based on the EDGAR HTAP global emission inventory, while dust and biogenic emissions are calculated online. Three simulations utilizing the CBMZ-MOSAIC, MOZART-MOSAIC, and RADM2-MADE/SORGAM gas-phase and aerosol mechanisms are performed. The results are compared with measurements from a dense observational network of 14 ground stations in Cyprus. The model simulates T 2 m , P surf , and WD 10 m accurately, with minor differences in WS 10 m between model and observations at coastal and mountainous stations attributed to limitations in the representation of the complex topography in the model. It is shown that the south-eastern part of Cyprus is mostly affected by emissions from within the island, under the dominant (60 %) westerly flow during summertime. Clean maritime air from the Mediterranean can reduce concentrations of local air pollutants over the region during westerlies. Ozone concentrations are overestimated by all three mechanisms (9 % ≤ NMB ≤ 23 %) with the smaller mean bias (4.25 ppbV) obtained by the RADM2-MADE/SORGAM mechanism. Differences in ozone concentrations can be attributed to the VOC treatment by the three mechanisms. The diurnal variability of pollution and ozone precursors is not captured (hourly correlation coefficients for O 3 ≤ 0.29). This might be attributed to the underestimation of NO x concentrations by local emissions by up to 50 %. For the fine particulate matter (PM 2.5 ), the lowest mean bias (9 µg m −3 ) is obtained with the RADM2-MADE/SORGAM mechanism, with overestimates in sulfate and ammonium aerosols. Overestimation of sulfate aerosols by this mechanism may be linked to the SO 2 oxidation in clouds. The MOSAIC aerosol mechanism overestimates PM 2.5 concentrations by up to 22 µg m −3 due to a more pronounced dust component compared to the other two mechanisms, mostly influenced by the dust inflow from the global model. We conclude that all three mechanisms are very sensitive to boundary conditions from the global model for both gas-phase and aerosol pollutants, in particular dust and ozone.

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Section: G K Georgiou Et Al: Summer Eastern Mediterranean Air Qualmentioning

confidence: 99%

Air quality modelling in the summer over the eastern Mediterranean using WRF-Chem: chemistry and aerosol mechanism intercomparison

et al. 2018

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“…A detailed description of the station is given by Mihalopoulos et al (1997) and Kouvarakis et al (2000). The station's suite of measurements includes ion speciation of aerosols, dry, and wet deposition measurements for the past 5 years (Kouvarakis et al, 2001) as well as ozone monitoring (Kouvarakis et al, 2000).…”

Section: Finokalia Sampling Stationmentioning

confidence: 99%

Aerosol sources and their contribution to the chemical composition of aerosols in the Eastern Mediterranean Sea during summertime

Sciare¹,

Bardouki

Moulin³

et al. 2003

Atmos. Chem. Phys.

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178

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Abstract.A detailed study on the temporal variability of compounds important in controlling aerosol chemical composition was performed during a one-month experiment conducted during summer 2000 at a background site on Crete, in the Eastern Mediterranean Sea. Contribution of different aerosol sources in the Eastern Mediterranean Basin could be investigated at this location since the site is influenced by a wide range of air masses originating mainly in Europe and Africa. Chemical apportionment was performed for various air mass origins and showed a strong impact of anthropogenic emissions in the Turkey and Central Europe sectors, with black carbon (BC) and non-sea-salt sulfate (nss-SO 4 ) concentrations higher than observed in the Eastern and Western Europe sectors. High levels of non-sea-salt calcium (nssCa) were associated with air masses from Africa but also from Central Turkey. Evidence was found that BC calculation based on light absorbance during dust events was biased.This quality-controlled high temporal resolution dataset allowed to investigate in detail the source-receptor relationships responsible for the levels of BC, nss-SO 4 and sulfur dioxide (SO 2 ), observed in Crete. Among the results obtained from this model, the major contribution of Turkey and Central Europe was confirmed in terms of anthropogenic emissions. Comparisons with remote optical properties obtained from Satellite observations (SEAWIFS) north of Crete indicates that our ground based aerosol characterization was suitable for describing aerosol properties in the atmospheric column for most of the time during the campaign.

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“…In the Mediterranean, the background surface ozone mixing ratios are the highest in Europe (Kouvarakis et al 2000(Kouvarakis et al , 2002Gerasopoulos et al 2005;Nolle et al 2002;Lelieveld et al 2002). According to Nolle et al (2005), the ozone mixing ratio in the Central Mediterranean might have increased by a factor of five over the last century.…”

Section: Introductionmentioning

confidence: 99%

A 10-year study of background surface ozone concentrations on the island of Gozo in the Central Mediterranean

et al. 2008

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A 10-year study of surface ozone mixing ratios in the Central Mediterranean was conducted based on continuous ozone measurements from 1997 to 2006 by a background regional Global Atmospheric Watch (GAW) station on the island of Gozo. The mean annual maximum mixing ratio is of the order of 66 ppbv in April-May with a broad secondary maximum of 64 ppbv in July-September. No long-term increase or decrease in the background level of surface ozone could be observed over the last 10 years. This is contrary to observations made in the Eastern Mediterranean, where a slow decrease in the background ozone mixing ratio was observed over the past 7 years. Despite the very high average annual ozone mixing ratio exceeding 50 ppbv-in fact, the highest average background ozone mixing ratio ever measured in Europe-, the diurnal O 3 max /O 3 min index of <1.40 indicates that the island of Gozo is a good site for measuring background surface ozone. However, frequent photosmog events from June to September during the past 10 years with ozone mixing ratios exceeding 90 ppbv indicate that the Central Mediterranean is prone to long-range transport of air pollutants from Europe by northerly winds. This was particularly evident during the so-called "August heatwave" of the year 2003 when the overall ozone mixing ratio was 4.6 ppbv higher than the average of all other 9 months of August since 1997. Air mass back-trajectory analysis of the August 2003 photosmog episodes on Gozo confirmed that ozone pollution originated from the European continent. Regression analysis was used to analyse the 10-year data set in order to model the behaviour of the ozone mixing ratio in terms of the meteorological parameters of wind speed, relative humidity, global radiation, temperature, month of year, wind sector,

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Temporal variations of surface regional background ozone over Crete Island in the southeast Mediterranean

Cited by 177 publications

References 25 publications

Air quality modelling in the summer over the eastern Mediterranean using WRF-Chem: chemistry and aerosol mechanism intercomparison

Air quality modelling in the summer over the eastern Mediterranean using WRF-Chem: chemistry and aerosol mechanism intercomparison

Aerosol sources and their contribution to the chemical composition of aerosols in the Eastern Mediterranean Sea during summertime

A 10-year study of background surface ozone concentrations on the island of Gozo in the Central Mediterranean

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