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The transport of tropospheric ozone, ozone precursors, carbon monoxide, etc from Asia to North America is an active area of research (see J.L. Ambrose, et al., 2011) These types of events occur rather dramatically in the springtime, apparently due to meteorological conditions when westerly winds are strong, which carries polluted air across the Pacific. Stratospheric ozone events can be differentiated because they have low moisture and no associated increase in carbon monoxide.

What meteorological factors contribute to the increased transport of Asia-generated air pollution to North America? What occurs meteorologically in the springtime that leads to more westerly transport than any other season? The analyses I've seen say that transport can occur anywhere from 2.5 km to 8 km above sea level.

Are there factors that could cause temporal or spatial shifts in how these types of pollution transport events are recepted in North America?

M. Lin et al., 2011 image

Image from M. Lin et al., 2011 publication showing carbon monoxide crossing the Pacific Ocean caught by Aqua/AIRS, (1018 molecules / cm2)

daniel.heydebreck
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f.thorpe
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  • Flow is from west (Asia) to east (America). – f.thorpe Oct 07 '15 at 15:28
  • so that would be the westerlies then. In your question you have mentioned easterlies. –  Oct 08 '15 at 00:02
  • how is the transport of pollutants from Asia during the rest of the year ? –  Oct 08 '15 at 12:54
  • @gansub there are still events that occur other times of the year... but my understanding is that late spring is when the transport is strongest due to meteorological conditions. I can find some other references if you think that would help. – f.thorpe Oct 08 '15 at 18:02
  • these westerly winds that move these pollutants - what geopotential height are they ? –  Oct 09 '15 at 00:11
  • Typically anywhere between 2.5km to 8km – f.thorpe Oct 09 '15 at 01:00
  • so mid troposphere to upper troposphere. –  Oct 09 '15 at 07:46
  • yes, but not near the UT/LS zone. – f.thorpe Oct 09 '15 at 14:32
  • does the jet stream's aerosol content - is that seasonal - I mean does it increase due to heating at the beginning of boreal summer ? –  Oct 31 '15 at 14:18
  • I'm not sure I understand your question – f.thorpe Oct 31 '15 at 19:18
  • is the concentration of aerosols much more at the beginning of boreal summer in the jet stream? –  Nov 01 '15 at 02:27
  • this question isn't about aerosols – f.thorpe Nov 29 '15 at 22:18
  • sorry about that. I had a thought it could be related to stratospheric tropospheric exchange and sudden stratospheric warmings. It is a guess at this time though. –  Nov 30 '15 at 05:17

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