1. INTERCONTINENTAL TRANSPORT OF OZONE AND ITS SEASONAL VARIATIONS IN EUROPE Dick Derwent rdscientific 2 nd ICAP Workshop Chapel Hill, North Carolina October 21 st -22 nd 2004 This work was sponsored by the United Kingdom Department for Environment, Food and Rural Affairs under contract CPEA 7.

2. STOCHEM three-dimensional global Lagrangian chemistry transport model fully coupled to Hadley Centre global atmosphere-ocean climate model or run from operational analyses from Met Office NWP model full chemistry of methane, ozone, 10 emitted VOCs, NO x, acid rain and secondary aerosol formation from SO 2, DMS, NH 3

3. OZONE LABELLING TECHNIQUES d/dt [O 3 ] = k 1 [HO 2 ][NO] + k 2 [RO 2 ][NO] – losses If air parcel is over North America then d/dt[O 3 America] = k 1 [HO 2 ][NO] + k 2 [RO 2 ][NO] – losses Otherwise d/dt[O 3 America] = - losses

4. Origins of European Ozone The origins of tropospheric background air across Europe 8 ppb 20 ppb 5 ppb 10 ppb

5. STOCHEM MODEL VS OBSERVATION FOR A RURAL LOCATION IN THE UNITED KINGDOM Harwell, Oxfordshire 1998

6. INTERCONTINENTAL ATTRIBUTION OF THE OZONE AT A RURAL UNITED KINGDOM LOCATION Harwell, Oxfordshire 1998

7. HOW CAN THESE MODEL PREDICTION OF INTERCONTINENTAL TRANSPORT BE VALIDATED ? Biomass burning during 1998 Halocarbon transport to Mace Head, Ireland

8. Mace Head, Ireland 1000s km uninterrupted fetch across North Atlantic Ocean Long range transport brings polluted air from Europe

9. BASELINE CONCENTRATIONS OF CO AND H 2 AT MACE HEAD, IRELAND

10. BASELINE CONCENTRATIONS OF CO 2 AND CH 4 AT MACE HEAD, IRELAND

11. BASELINE CONCENTRATIONS OF OZONE AT MACE HEAD, IRELAND

12. MONTHLY MEAN BASELINE O 3 CONCENTRATIONS EXPRESSED AS ANOMALIES FROM 1990-1999 MEANS Mace Head, Ireland, all hours

13. MONTHLY MEAN DAILY MAXIMUM O 3 CONCENTRATIONS FOR THE 54 EMEP STATIONS EXPRESSED AS ANOMALIES FROM THE 1990-1999 MEANS

14. MONTHLY MEAN DAILY MAXIMUM O 3 CONCENTRATIONS FOR THE UK RURAL SITES EXPRESSED AS ANOMALIES FROM THE 1990-1999 MEANS

15. NO 2 -O 3 -O x -NO x ANALYSES FOR BRIDGE PLACE, LONDON Jenkin et al. (2004)

16. CH 2 Cl 2 AT MACE HEAD, IRELAND DURING 1998 January December GC-MS observations from Prof Peter Simmonds

17. CH 2 Cl 2 IN STOCHEM WITH INTERCONTINENTAL LABELLING Peaks are European in origin

18. CH 2 Cl 2 FLUCTUATIONS CLOSE TO THE BASELINE Transport from North America

19. LAGRANGIAN DISPERSION MODEL NAME employs same meteorological fields as STOCHEM simulates transport and dispersion using upwards of a million air parcels released at unit density in a model domain that stretches across the North Atlantic Ocean plots show air concentration at Mace Head produced by unit density emissions at that point

21. GC-MS OBSERVATIONS OF CH 2 Cl 2 DURING MARCH 1998 Prof Peter Simmonds Intercontinental transport from USA

22. HALOCARBONS AS TRACERS OF INTERCONTINENTAL TRANSPORT Short atmospheric lifetimes means that their baseline concentrations are low compared to current global annual emission rates GC-MS has the sensitivity to observe them at ppt levels current USA emission rates are significant for some halocarbons, particularly HFCs

23. INTERCONTINENTAL TRANSPORT OF OZONE ON 14-15 JULY 2004 FROM NEW YORK-BOSTON TO MACE HEAD 14th July15 th July

24. CONCLUSIONS Modelling studies point to the importance of intercontinental transport in influencing the distribution of ozone in Europe This influence extends to its seasonal variations and trends with time The observations of reactive halocarbons are now available at Mace Head to study intercontinental transport on a systematic basis Aim is the validate the models of intercontinental transport across the North Atlantic Ocean