1. Long-range transport of NO y and O 3 Thomas Walker Dalhousie University Department of Physics & Atmospheric Science December 6, 2006

2. What effect do increasing Asian NO x emissions have on air quality in the Pacific?

3. DC8: ● TD-LIF (NO 2, PN's, HNO 3 ) ● SAGA (HNO 3 ) ● O 3 C130: ● NO x /NO y /O 3 ● PAN-CIGARette

4. DC8 Campaign Average Vertical Profiles: Ozone

5. DC8 Campaign Average Vertical NO y Composition Profile

6. C130 Campaign Average Vertical Profiles: Ozone

7. C130 Campaign Average Vertical NO y Composition Profile

8. “Streets” replace “standard” emissions with Streets inventory over Asia [~7.50 Tg N/yr] Δ Emissions [Tg N/yr] “Standard” use latest scaling for lightning and biomass burning [~7.64 Tg N/yr] Emissions [Tg N/yr] “No Asia” turn off Asian fossil fuel emissions entirely Emissions [Tg N/yr]

9. Fractional Change in Model Due to Change in Asian Emissions

10. Fractional Change in Model Due to Turning Off Asian Emissions

11. Lightning's Contribution

12. Comparison to Ozone Monitoring Instrument (OMI)

13. OMI compared to model

14. ● Summary ● O 3 in model biased 5-10 ppb low relative to aircraft ● O 3 columns in model low relative to OMI ● Significant contributions from lightning and Asian transport ● HNO 3 in model biased high relative to aircraft ● HNO 3 profile in model sensitive to changes in Asian emissions ● Future Work ● Further decomposition of O 3 columns: biomass burning, local srcs ● Comparison of model NO 2 to OMI ● Examine potential HNO 3 sinks: uptake on dust

15. Special thanks to: Atmospheric Chemistry Analysis Group Randall Martin Bastien Sauvage Rong-Ming Hu Lok Lamsal Betty Croft Aaron van Donkelaar Neil Moore Gray O'Byrne Balagopal Pillai Thank You for listening!

16. References ● Jacob, D. Introduction to Atmospheric Chemistry. Princeton University Press, 1999. ● Martin, R.V. et al. Space-based constraints on the production of nitric oxide by lightning. Submitted to JGR, 2006. ● Hudman, R.C. et al. Surface and lightning sources of nitrogen oxides over the United States: magnitudes, chemical evolution, and outflow. Submitted to JGR, 2006.

17. DC8 Vertical Profiles: NOx

18. DC8 Vertical Profiles: HNO 3

19. DC8 Vertical Profiles: PNs

20. C130 Vertical Profiles: NOx

21. C130 Vertical Profiles: HNO3

22. C130 Vertical Profiles: PNs

24. Standard features: ● Assimilated meteorology (GEOS-4) ● NO x -O x -HC tropospheric chemistry ● 4x5 resolution (for expediency) ● 30 vertical levels, parametrized strat ● Planeflight diagnostic Model version v7-04-10 Recent updates include: ● Near-land lightning parametrization ● High-latitude lightning rescaling ● Rescaling of biomass burning emissions ● Use of Streets inventory

25. Ref: Richter et al. 2005. Increase in Asian NO 2 columns observed from GOME/SCIAMACHY

26. Long-range transport Deposition Rate-limiting step is rxn of NO w. HO 2 radical P(O 3 ) NO x -limited: P(O 3 ) goes as [NO] HC-limited: P(O 3 ) goes as [RH]/[NO 2 ] P(O 3 ) N2ON2O NO NO 2 N2O5N2O5 HNO 3 PAN NO x NO y

27. OMI compared to “standard” model

28. ● Motivation ● Modelling ● Introduction to GEOS-CHEM ● Comparison of measurements to standard model ● Description of model experiments ● Results from model experiments ● Satellite ● Comparison of model to OMI Ozone ● Summary and future directions