1. Introduction: models and measurements

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1 GRG Global modelling of air pollution during the European heat wave of summer 2003 C. Ordóñez1, O. Stein2,3, J. P. Cammas1, A. Dethof4, J. Flemming4, H. Flentje5, E. Katragkou6, M. G. Schultz3, A. Segers7, and M. van Weele7 (1) Laboratoire d'aérologie, CNRS, France; (2) MPI-M, Germany; (3) Forschungszentrum Jülich, Germany; (4) ECMWF, UK, (5) DWD, Germany; (6) Univ. of Thessaloniki, Greece; (7) KNMI, NL

2 1. Introduction: models and measurements 4 model runs used MOZART º X 1.895º 60 vertical levels TM5 3º lon X 2º lat 60 vertical levels MOZART hr MOZART run with improved resolution: 1.125º X 1.125º TM5 hr Same TM5 run but with zoom to 1º X 1º over the European domain For all models: Monthly emissions (RETRO and GFEDv2 wildfires) Meteo forcing from a ECMWF reanalysis for GEMS Comparison with MOZAIC vertical profiles Profiles above: Frankfurt (also Paris & Vienna) Parameters: mainly O 3 and CO (also T, RH, wind speed) Only data for 9-18 UTC Comparison with surface measurements Surface O 3 from EMEP and GAW ; O 3 and NO x from NRW air quality stations Comparison with EURAD regional CTM Surface O 3 and NO x for NRW

3 2. Meteorology during the heat wave Summer 2003 was anomalously warm and dry in Europe Luterbacher et al. [Science, 2004]: Summer 2003 was very likely warmer than any other summer during the last 500 years. Schär et al. [Nature, 2004] and other papers: Strong thermal anomalies over central Europe in Jun and Aug Chase et al. [GRL, 2006]: The European heat wave of summer 2003 was a deep tropospheric phenomenon, with strong JJA T anomalies within hpa. IPCC [2007]: Very likely, that heat waves over Europe have a longer duration / are more intense / are more frequent in a changing climate Strongest meteo anomalies during the first fortnight of August [Trigo et al., GRL, 2005]: Anom. for 1-15 Aug 2003 (wrt ) of: 850 hpa T ( C) 500 hpa Ф (gpm)

4 Analysis of MOZAIC profiles above Frankfurt and Lagrangian dispersion model simulations for 16 July 31 Aug 2003 [Tressol et al., submitted to ACP, 2007]: before hw (16 31 July) during hw (2 14 Aug) after hw (16 31 Aug) Heat wave period suppressed LRT in mid- to lower troposphere (FLEXPART) high T, low RH and low wind speed (MOZAIC profiles)

5 T, RH and wind speed at 850 hpa above Frankfurt MOZAIC TM5 MOZART

6 3. Air pollution during the heat wave Ozone: Comparison with EMEP & GAW surface measurements

7 Evolution of surface O 3 for the 3 heat wave periods

8 Evolution of surface CO for the 3 heat wave periods

9 Time series of 850 hpa O 3 / CO above Paris and Frankfurt MOZAIC TM5 TM5 hr MOZART MOZART hr Frontal transport from Portuguese fires Ventilation (low-pressure system)

10 Vertical O 3 profiles above Frankfurt during the heat wave hpa hpa >850 hpa

11 Vertical CO profiles above Frankfurt during the heat wave r = r = r = MOZ+IFS+ASSIM z (m) hpa hpa MOZ+IFS MOZART hr MOZART TM5 hr TM5 MOZAIC CO (ppb)

12 Vertical CO profiles above Frankfurt during the heat wave r = r = r = MOZ+IFS+ASSIM z (m) hpa hpa MOZ+IFS MOZART hr MOZART TM5 hr TM5 MOZAIC CO (ppb)

13 Vertical CO profiles above Frankfurt during the heat wave r = r = r = MOZ+IFS+ASSIM z (m) hpa hpa MOZ+IFS MOZART hr MOZART TM5 hr TM5 MOZAIC CO (ppb)

14 Vertical CO profiles above Frankfurt during the heat wave r = r = r = MOZ+IFS+ASSIM z (m) hpa hpa MOZ+IFS MOZART hr MOZART TM5 hr TM5 MOZAIC CO (ppb)

15 Vertical CO profiles above Frankfurt during the heat wave r = r = r = MOZ+IFS+ASSIM z (m) hpa hpa MOZART+IFS MOZART hr MOZART TM5 hr TM5 MOZAIC CO (ppb) GEMS-GRG coupled system (IFS - MOZART): exchange of meteo. fields and chem. tendencies at 1h intervals Assimilation of column retrievals of O 3 and CO (also HCHO and NO 2 in the future)

16 Vertical CO profiles above Frankfurt during the heat wave r = r = r = MOZART+IFS+assim z (m) hpa hpa MOZART+IFS MOZART hr MOZART TM5 hr TM5 MOZAIC CO (ppb) GEMS-GRG coupled system (IFS - MOZART): exchange of meteo. fields and chem. tendencies at 1h intervals Assimilation of column retrievals of O 3 and CO (also HCHO and NO 2 in the future)

17 4. How to approach reality? 1. Introduction: 4. models and measurements Some well-known deficiencies in the CTMs : GRG Limited horizontal resolution compared with regional models. Models use monthly anthropogenic emissions (no daily cycle and day-to-day variability). No realistic emissions of biogenic VOCs (Guenther/MEGAN algorithms not included) Evaporative emissions of anthropogenic VOCs might increase due to the high T. A more realistic dry deposition that accounts for the dryness of vegetation might be needed in the models (see e.g. Vautard et al. [Atm. Env. 2005] and Solberg et al. [submitted to JGR, 2007]). Contribution of transport from Portuguese fires [Hodzic et al., ACP, 2006, 2007; Tressol et al., submitted to ACP, 2007]. Current model setup without injection heights and with monthly fire emissions. A new MOZART run with some improvements is ongoing. Sensitivity runs for process understanding Important, since an increase in the number of heat wave episodes is predicted by the mid/end of the century under unmitigated GHG emissions [Schär et al., 2004; Stott et al., 2004; IPCC, 2007]. Comparison to regional models

18 Surface O 3 (ppb) Comparison to NRW air quality station measurements MOZART hr (1.125 ) Latitude ( N) FZJ K h h Longitude ( E) EURAD (5 km) ppb station mean (33/25 stations)

19 5. Conclusions and outlook Strong anomalies in meteo parameters (T, RH, wind speed), suppression of LRT and enhancement of pollution over Western/Central EU during the period 2-14 Aug (approx.). MOZART and TM5 reproduce cycles (but not peaks) of O 3 and CO. MOZART t106 wrt MOZART t63: Enhanced levels of O 3, CO and other pollutants (e.g. HCHO, NO y ) close to the ground. Most probably, better simulation of transport and residence of air masses in the PBL. Reproducing CO levels remains a problem for the CTMs, particularly for TM5. Possible explanations include flaws in the chemistry scheme, CO or VOC emissions. In addition there are large uncertainties in the biogenic fluxes during the heatwave (VOC emissions, O 3 deposition). Some improvements with the coupled-assimilation system. The GEMS-GRG coupled-assim. system will provide boundary conditions for regional air quality models on an operational basis.

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21 Some of the statistics considered 2 MNMB = N i f i oi 100% fi + oi Modified normalised mean bias 2 FGE = N i fi oi f + o i i 100% Fractional gross error 1 MB = ( f i o i ) 100% N i 1 RMSE = ( f i o i ) N i 2 1/ 2 100% Mean bias Root mean square error Only used for T (MNMB and FGE can be very large for T because this parameter can be posit and negat). Used not here but in the file that I send you with info on T in the models.

22 Vertical CO profiles above Frankfurt during the heat wave hpa hpa >850 hpa

23 Evolution of 500 m agl O 3 for the 3 heat wave periods

24 Evolution of dry deposition velocity for O 3 in MOZART (March Aug 2003)

25 Evolution of dry deposition velocity for O 3 in TM5 (June Aug 2003)

26 European Anthropogenic CO tracer (estimated with FLEXPART) Biomass burning CO tracer (estimated with FLEXPART) Tressol et al. [submitted to ACP, 2007]