University of Athens 2 ND GEOS-CHEM users Meeting 1 Nesting GEOS-CHEM with a regional air pollution model for Greece Maria Tombrou, Elissavet Bossioli, Anna Protonotariou, Elena Flocas and Aggeliki Dandou University of Athens Christos Giannakopoulos National Observatory of Athens

University of Athens 2 ND GEOS-CHEM users Meeting 2 What we Know Critical factors for high levels of photochemical pollutants in the GAA: – poor ventilation – frequent appearance of the sea breeze – intense solar irradiation – intense anthropogenic activities The long range transport of ozone precursors, from the Western European continent over the Eastern Mediterranean, contributes significantly in high ozone concentrations. What we don’t know It is unclear yet which mechanism contributes the most the reasons for underestimating ozone concentration during episodes

University of Athens 2 ND GEOS-CHEM users Meeting 3 Emission inventory (point sources) SO 2 (moles/h)

University of Athens 2 ND GEOS-CHEM users Meeting 4 Emission inventory (area anthropogenic) NO X (moles/h/4km 2 )

University of Athens 2 ND GEOS-CHEM users Meeting 5 Emission inventory (biogenic) Isoprene (kg/h/36km 2 ) Terpenes (kg/h/36km 2 )

University of Athens 2 ND GEOS-CHEM users Meeting 6 Numerical experiments (MM5/UAM) Base case: only anthropogenic emissions Numerical experiments: –Biogenic emissions –VOC’s speciation in urban areas and aged plumes –Background O 3 concentration levels –Various sets of meteorological fields (different nesting, urban sector effects on the wind speed and diffusion coefficient, increase the depth of first layer)

University of Athens 2 ND GEOS-CHEM users Meeting 7 Diurnal variation of O3 concentrations at a suburban station of Athens on

University of Athens 2 ND GEOS-CHEM users Meeting 8 Diurnal variation of O3 by GEOS – CHEM over Greece (1-6) FIG. 7 : Diurnal variation of O 3 concentrations as calculated by GEOS –CHEM over Greece (1-6) on FIG. 7 : Diurnal variation of O 3 concentrations as calculated by GEOS –CHEM over Greece (1-6) on FIG. 7 : Diurnal variation of O 3 concentrations as calculated by GEOS –CHEM over Greece (1-6) on FIG. 7 : Diurnal variation of O 3 concentrations as calculated by GEOS –CHEM over Greece (1-6) on FIG. 7 : Diurnal variation of O 3 concentrations as calculated by GEOS –CHEM over Greece (1-6) on FIG. 7 : Diurnal variation of O 3 concentrations as calculated by GEOS –CHEM over Greece (1-6) on

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University of Athens 2 ND GEOS-CHEM users Meeting GEOS – CHEM results

University of Athens 2 ND GEOS-CHEM users Meeting 11 Concentrations of O 3 (μgr/m 3 ) at 15:00LST Boundary inflow from GEOS-CHEM Boundary inflow constant

University of Athens 2 ND GEOS-CHEM users Meeting 12 Concentrations of O 3 (μgr/m 3 ) at 15:00LST Boundary inflow from GEOS-CHEM Boundary inflow constant

University of Athens 2 ND GEOS-CHEM users Meeting 13 Future work Develop the nesting capability for the Mediterranean region (1 o x1 o ) Insert EMEP emissions over Europe and the new inventory of Greece (at the appropriate levels) Link GEOS-CHEM with CAMx; UAM Perform O3 sensitivity runs