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
Jan 17, 2016
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
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M. Osman, W. Hocking, D.Tarasick, J.Drummond
Outline
Background and Motivation
Methods
Results
Future Work
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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
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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
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MethodsOzonesondes combined with windprofiler radars
Radar analysis software and MATLAB
1 Ozone sensor Styrofoam casing2 Radiosonde3 Ozonesonde Interface Board OIF114 Ozone sensor
Windprofiler radar at Eureka
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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
ResultsARC-IONS
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
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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
Was the leakage due to high concentration of ozone immediately above the
tropopause ?
No!
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Was the ozone really stratospheric?
Low RH used as a partial indicator of ozone originated from stratosphere
Weak gradients of ozone
Low humidity…
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Smoothed humidity…ARC-IONS
Ozone & Humidity …
Low humidity?
Is there a correlation?
High tropospheric ozone
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Smoothed one…ARC-IONS
Was the tropopause poorly defined?
Gradient of temperature around tropopause is not that weak in Feb – Mar…
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Cont…
Gradient of temperature around tropopause is not that weak…
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Turbulence
No obvious distinction between the two periods!
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Proxy for gravity waveSD of vertical component of wind
Nothing distinct statistically between the two periods!
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ARC-IONS Vertical Wind (1-5km)
No obvious difference between the two periods!
ARC-IONS Vertical Wind (5-10km)
No difference!
Horizontal Wind (1 – 5km)ARC-IONS
ARC-IONS Horizontal Wind (5 – 10km)
During April 1–13 the wind was blowing northward!
Daily Horizontal Wind (1 – 5km)ARC-IONS
ARC-IONS Daily Horizontal Wind (5 – 10km)
During the 1st two weeks of April northward blowing wind quite dominant
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
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Acknowledgements
Prof. Wayne Hocking
Prof. David Tarasick
University of Western Ontario
Environment Canada
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Thank you!
Horizontal Wind (5 – 10km)ARC-IONS
Daily Horizontal Wind (5 – 10km)ARC-IONS
From 04/01 – 04/13 the wind was blowing northward
Turbulence 5 - 10kmARC-IONS
Turbulence up to 15kmARC-IONS
ARC-IONS Horizontal Wind (1 – 5km)
Although it isn’t quite dominant the wind was blowing northward!
ARC-IONS Daily Horizontal Wind (1 – 5km)
The wind was blowing northward!
Vertical Wind (1-5km) ARC-IONS
Vertical Wind (5-10km)ARC-IONS
Vertical Wind (1-10km)ARC-IONS
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Horizontal Wind (1 – 10km)ARC-IONS
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Daily Horizontal Wind (1 – 10km)ARC-IONS
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Horizontal Wind
From 04/01 – 04/13 the wind was blowing northward
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Horizontal Wind…
During the 1st two weeks April northward blowing wind quite dominantBefore coming to conclusion we need to look at in more detail
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