Blog
About

  • Record: found
  • Abstract: found
  • Article: not found
Is Open Access

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

Read this article at

ScienceOpenPublisher
Bookmark
      There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

      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<sub>2 m</sub>, P<sub>surf</sub>, and WD<sub>10 m</sub> accurately, with minor differences in WS<sub>10 m</sub> 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<sub>3</sub>  ≤  0.29). This might be attributed to the underestimation of NO<sub><i>x</i></sub> concentrations by local emissions by up to 50 %. For the fine particulate matter (PM<sub>2.5</sub>), the lowest mean bias (9 µg m<sup>−3</sup>) 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<sub>2</sub> oxidation in clouds. The MOSAIC aerosol mechanism overestimates PM<sub>2.5</sub> concentrations by up to 22 µg m<sup>−3</sup> 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.

      Related collections

      Most cited references 48

      • Record: found
      • Abstract: not found
      • Article: not found

      Radiative transfer for inhomogeneous atmospheres: RRTM, a validated correlated-k model for the longwave

        Bookmark
        • Record: found
        • Abstract: not found
        • Article: not found

        Coupling an Advanced Land Surface–Hydrology Model with the Penn State–NCAR MM5 Modeling System. Part I: Model Implementation and Sensitivity

          Bookmark
          • Record: found
          • Abstract: not found
          • Article: not found

          A New Vertical Diffusion Package with an Explicit Treatment of Entrainment Processes

            Bookmark

            Author and article information

            Journal
            Atmospheric Chemistry and Physics
            Atmos. Chem. Phys.
            Copernicus GmbH
            1680-7324
            2018
            February 02 2018
            : 18
            : 3
            : 1555-1571
            10.5194/acp-18-1555-2018
            © 2018

            https://creativecommons.org/licenses/by/4.0/

            Product

            Comments

            Comment on this article