Long-Range Transport of Asian Sulphate to Canada

1
Long-Range Transport of Asian Sulphate to Canada

• Aaron van Donkelaar, Randall V. Martin, Thomas
  Walker Dalhousie University
• W. Richard Leaitch, Anne Marie Macdonald
  Environment Canada
• David G. Streets, Qiang Zhang Argonne National
  Laboratory
• Edward Dunlea, Jose L. Jimenez University of
  Colorado
• Jack E. Dibb University of New Hampshire
• Greg Huey, Rodney Weber Georgia Institute of
  Technology
• Meinrat O. Andreae Max Plank Institute for
  Chemistry

CAFC Meeting 31 March 2008
2
Intercontinental Chemical Transport Experiment
(INTEX-B) April-May 2006
King Air (May 1985) SO4 (filters)
Cessna SO4 (Q-AMS)
Whistler Summit SO4 (MOUDI)
DC-8 SO4 (filters, mist chamber)
C-130 SO4 (HR-ToF-AMS, PILS)
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Trans-Pacific Sulphate Observed at Whistler?
H2O Concentration g H2O/kg
0 3 6
SO4
4 3 2 1
Altitude km
Org
NH3
0 1 2 3
Mass Concentration µg/m3
4
Average over April 22 - May 15 AM at Whistler
(20 flights)
Increasing Aerosol Size with Altitude
Richard Leaitch
5
Sulphate and Calcium at Whistler Summit (2182m)
Richard Leaitch
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Simulated (GEOS-Chem) Sulphate Transport
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Sulphate Major Component of East Asian AOD
Model (GEOS-Chem)
MODIS
MISR
GC Bias 12MODIS 22 MISR
Model held at 2000 anthropogenic emissions
r0.68
MODIS MISR All Dust Model SO4
r0.60
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Fall AOD Trend Reflects Increasing Asian SO2
EmissionsConsistent with Subsequent Bottom-up
Estimate
Model held at 2000 anthropogenic emissions
MODIS MISR All Dust Model SO4
6.2 9.6 emission growth per year
9
Campaign Mean SO4 in Free Trop Primarily
AsianLower Tropospheric Transport over Ocean,
Increasing Altitude at NA

• Filter Pack (lt4.5 um) higher than unscaled Mist
  Chamber (lt 1um)
• C-130 and Cessna measurements scaled by 1.4
• 60-70 of SO4 of East Asian origin at 600 hPa

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East Asian SO4 Fraction Increased by 2.4x 3.4x
Since 1985
C-130 (May 2006)
King (May 1985)
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Long-Range Transport Affects NA Sulfate Burden
SO4 at 2.0 km

• GEOS-Chem April-May 2006
• Persistent East Asian contribution at 4 km
• Near Vancouver
• 25-30 of surface sulfate of east Asian origin
• 40 of sulfate burden (1-5 km) of east Asian
  origin

SO4 µg/m3
Altitude km
Altitude km
Asian SO4
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Conclusions

• Trend in East Asian AOD appears to reflect
  increasing SO2 emissions
• 2.4-3.4x increase in the relative contribution of
  East Asian sulfate since 1985
• Pacific basin may contain trends in aerosol-cloud
  feedbacks