1. Long-range transport of ozone from the Los Angeles Basin: A case study A.O. Langford 1, C. J. Senff 2, R.J Alvarez 1 II, R. M. Banta 1, R.M. Hardesty 1 1 Chemical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, Colorado, USA 2 Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, and Chemical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, Colorado, USA

2. Pre-CalNex flights coincided with highest ozone in SCAB during all of 2009 27 of 31 days in July exceeded NAAQS in South Coast Air Basin

3. 2009 High ozone episode 15 July: 1-hr 116 ppbv 8-hr 100 ppbv

4. 2009 High ozone episode 16 July: 1-hr 124 ppbv 8-hr 90 ppbv

5. 2009 High ozone episode 17 July: 1-hr 149 ppbv 8-hr 111 ppbv

6. 2009 High ozone episode 18 July: 1-hr 150 ppbv 8-hr 128 ppbv* * 2009 high value

7. 2009 High ozone episode 19 July: 1-hr 146 ppbv 8-hr 110 ppbv

8. 2009 High ozone episode 20 July: 1-hr 115 ppbv 8-hr 83 ppbv

9. San Gabriel Mountains from Pomona CA (1910)

10. Twin Otter over San Gabriel Mountains on 17 July 2009

11. Flight track 17 July 2009

12. TOPAZ Aerosol 17 July

13. TOPAZ Ozone 17 July

15. TOPAZ Ozone 17 July 2009

16. UCLA SMOG Model 27 Aug 1987 SCAQS Lu and Turco 1996

17. UCLA SMOG Model Lu, Turco, and Jacobson 1994-1996 Integrated model with: Mesoscale meteorology Boundary layer physics Tracer advection Convection and diffusion Photochemistry Aerosol microphysics and chemistry Solar and terrestrial radiative transfer

18. UCLA SMOG Model Lu, Turco, and Jacobson 1994-1996 85 x 55 grid cell meteorological domain 51 x 31 grid cell tracer chemistry domain Horizontal resolution ~0.05° (~5 km) 20 non-uniform vertical layers

19. Synoptic Background 00 UT 18 July 200900 UT 27 August 1987 1000 hPa

20. Synoptic Background 00 UT 18 July 200900 UT 27 August 1987 700 hPa

21. Where does the ozone go? 48 h HYSPLIT forward trajectories

23. 24 hours later

24. Where does the ozone go? 48 h HYSPLIT forward trajectories 48 hours later

25. Where does the ozone go? 48 h HYSPLIT backward trajectories

26. Where does the ozone go? 48 h HYSPLIT forward trajectories

27. How often does this occur? What about 19 July 2009

28. Flight track 19 July 2009

29. TOPAZ Aerosol 19 July

30. TOPAZ Ozone 19 July

31. Synoptic Background 00 UT 18 July 2009 00 UT 20 July 2009 1000 hPa

32. Synoptic Background 00 UT 18 July 2009 00 UT 20 July 2009 700 hPa

33. Questions for CalNex What conditions are needed for “Mountain Chimney Effect”? What conditions favor long range transport from the Los Angeles Basin? How well can WRF/Chem reproduce these observations?