1. Stratospheric–Tropospheric Exchange of Ozone during February–April 2008 at Eureka University of Western Ontario Environment Canada University of Dalhousie ARC-IONS Workshop 7-8 January 2009 ARC-IONS M. Osman, W. Hocking, D.Tarasick, J.Drummond

2. Outline  Background and Motivation  Methods  Results  Future Work ARC-IONS

3. Background and Motivation  Photochemistry is the major source of ozone in the lower troposphere  The stratosphere–troposphere exchange of ozone  Health issues  Economic issues- crop production  Global warming ARC-IONS

4. Detection of Ozone intrusion Source: Hocking et al. (2007)- NATURE Simultaneous radar and ozonesonde measurements from the Montreal Campaign of April–May 2005 This talk examines the detection of stratospheric ozone leakage from the stratosphere to the troposphere Particularly highlighting noticeable differences between February-March and April ARC-IONS

5. Methods  Ozonesondes combined with windprofiler radars  Radar analysis software and MATLAB 1 Ozone sensor Styrofoam casing 2 Radiosonde 3 Ozonesonde Interface Board OIF11 4 Ozone sensor Windprofiler radar at Eureka ARC-IONS

6. Ozone campaign 24 Feb – 18 April 2008 Eureka  Ozone variation with height  Time series of ozone concentration between ground & 0.5km as well as 0.5km & 1.0km Results ARC-IONS

7. Ozone plot  Red transition to softer colors …noticeable Smeared out A lot more ozone in the upper and middle troposphere High gradients of ozone Sharp cut off ARC-IONS

8.  Was the difference due to ozone concentration just above the tropopause?  Was it stratospheric ozone?  What happened to tropopause during those periods of time?  Wind and turbulence strengths Motivated questions… ARC-IONS

9. Was the leakage due to high concentration of ozone immediately above the tropopause ? No! ARC-IONS

10. Was the ozone really stratospheric?  Low RH used as a partial indicator of ozone originated from stratosphere Weak gradients of ozone Low humidity… ARC-IONS

11. Smoothed humidity… ARC-IONS

12. Ozone & Humidity … Low humidity? Is there a correlation? High tropospheric ozone ARC-IONS

13. Smoothed one… ARC-IONS

14. Was the tropopause poorly defined? Gradient of temperature around tropopause is not that weak in Feb – Mar… ARC-IONS

15. Cont… Gradient of temperature around tropopause is not that weak… ARC-IONS

16. Turbulence No obvious distinction between the two periods! ARC-IONS

17. Proxy for gravity wave SD of vertical component of wind Nothing distinct statistically between the two periods! ARC-IONS

18. Vertical Wind (1-5km) No obvious difference between the two periods!

19. ARC-IONS Vertical Wind (5-10km) No difference!

20. Horizontal Wind (1 – 5km) ARC-IONS

21. Horizontal Wind (5 – 10km) During April 1–13 the wind was blowing northward!

22. Daily Horizontal Wind (1 – 5km) ARC-IONS

23. Daily Horizontal Wind (5 – 10km) During the 1 st two weeks of April northward blowing wind quite dominant

24. Future Work To further analyze the wind and turbulent strengths To simulate the situation using FLEXPART To run photochemical models like GEM- MACH To apply the same procedure for other radar stations and campaigns ARC-IONS

25. Acknowledgements  Prof. Wayne Hocking  Prof. David Tarasick  University of Western Ontario  Environment Canada  ARC-IONS Thank you!

26. Horizontal Wind (5 – 10km) ARC-IONS

27. Daily Horizontal Wind (5 – 10km) ARC-IONS From 04/01 – 04/13 the wind was blowing northward

28. Turbulence 5 - 10km ARC-IONS

29. Turbulence up to 15km ARC-IONS

30. Horizontal Wind (1 – 5km) Although it isn’t quite dominant the wind was blowing northward!

31. ARC-IONS Daily Horizontal Wind (1 – 5km) The wind was blowing northward!

32. Vertical Wind (1-5km) ARC-IONS

33. Vertical Wind (5-10km) ARC-IONS

34. Vertical Wind (1-10km) ARC-IONS

36. Horizontal Wind (1 – 10km) ARC-IONS

38. Daily Horizontal Wind (1 – 10km) ARC-IONS

40. Horizontal Wind From 04/01 – 04/13 the wind was blowing northward ARC-IONS

41. Horizontal Wind… During the 1 st two weeks April northward blowing wind quite dominant Before coming to conclusion we need to look at in more detail ARC-IONS