Transcript Long-Range Transport of Asian Sulfate and Its Effects on

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
Intercontinental Chemical Transport Experiment (INTEX−B)
April-May 2006
Cessna
DC-8
C-130
SO4= (filters,
mist chamber)
SO4= (HR-ToF-AMS, SO4= (Q-AMS)
PILS)
Whistler
Summit
King Air
(May 1985)
SO4= (MOUDI) SO4= (filters)
Trans−Pacific Sulphate Observed at Whistler?
H2O Concentration [g H2O/kg]
0
3
6
SO4=
Altitude [km]
4
3
Org
2
NH3
1
0
1
2
3
Mass Concentration [µg/m3]
Increasing Aerosol Size with Altitude
Average over April 22 - May 15 AM at Whistler (20 flights)
April 22-May 15 averages
April 22 - May 15 averages
6000
6000
5000
5000
Total >120 nm
Total >15 nm
Number >1um
Sulphate
Organics
Nitrate
Ozone/100
3000
4000
Altitude (m-MSL)
Altitude (m-MSL)
4000
3000
2000
2000
1000
1000
0
0
0
0.2
0.4
0.6
0.8
1
1.2
Number Cn (cm-3); Mass Cn (mg/m-3); Ozone (ppbv)
1.4
0
500
1000
1500
2000
2500
3000
-3
Number concentrations (cm )
Richard Leaitch
Sulphate and Calcium at Whistler Summit (2182m)
0.2
>3 mm
y = 1.152x - 0.0181
R2 = 0.8589
0.18
> 3 microns
1-3 microns
0.16
<1 micron
3
Calcium (mg/m )
0.14
0.12
0.1
<1 mm
y = 0.0008x + 0.0317
R2 = 5E-05
1-3 mm
y = 0.2102x + 0.0159
R2 = 0.3822
0.08
0.06
0.04
0.02
0
0
0.2
0.4
0.6
0.8
1
1.2
Sulphate (mg/m3)
Richard Leaitch
Simulated (GEOS-Chem) Sulphate Transport
Sulphate Major Component of East Asian AOD
Model (GEOS-Chem)
MODIS
MISR
GC Bias
12%MODIS
22% MISR
Model held at 2000 anthropogenic emissions
MODIS r=0.68
MISR
r=0.60
All
Dust Model
SO4=
Fall AOD Trend Reflects Increasing Asian SO2 Emissions
Consistent 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
Campaign Mean SO4= in Free Trop Primarily Asian
Lower Tropospheric Transport over Ocean, Increasing Altitude at NA
Aircraft
Full Emissions
No East Asia
No Anthro.
Model
Filter Pack (<4.5
um) higher than
unscaled Mist
Chamber (< 1um)
C-130 and Cessna
measurements
scaled by 1.4
60-70% of SO4= of
East Asian origin
at 600 hPa
East Asian SO4= Fraction Increased by 2.4x – 3.4x Since 1985
C-130 (May 2006)
King (May 1985)
Aircraft
Full Emissions
No East Asia
No Anthro.
Model
SO4= [µg/m3]
•
•
% Asian SO4=
Altitude [km]
Altitude [km]
SO4= at 2.0 km
Long−Range Transport Affects NA Sulfate Burden
•
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
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