Long-Range Transport of Sulfate to CanadaGEOS-Chem Users Meeting

Aaron van DonkelaarDalhousie University

April, 2007

SO2 emission inventories out of date Inventories used by GEOS-Chem

• Global Inventories– GEIA (1985)

– EDGAR (2000)

• Regional Inventories– Bravo (Mexico, 1999)

– Streets (East Asia, 2000)

– NEI99 (USA, 1999)

NEI99

BRAVO

Streets

Generation of Scale FactorsScale factors are used to approximate emission changes from the base year of

the inventories.

0.6

0.8

1

1.2

1.4

1.6

1.8

1999 2000 2001 2002 2003

Year

Unregulated SO2 Scalar

Canada

China

India

Japan

USA

Regulated: limit pollutant emission (i.e. SOx, NOx, CO)

• USA, Canada, Europe, Japan, etc.

• Generate emission reports– EPA Acid Rain Program– The Canada-Wide Acid Rain

Strategy– European Monitoring and

Evaluation Program (EMEP)

Unregulated: no emission controls

• Asia, Africa, etc.

• Must infer emissions changes from secondary sources, such as CDIAC CO2 emissions.

– NOx: total CO2

– CO: liquid CO2

– SOx: solid CO2

0.6

0.8

1

1.2

1.4

1.6

1.8

1999 2000 2001 2002 2003

Year

RegulatedSO2 Scalar

Canada

Japan

USA

SOx Emissions Scalar (2000-2002)

INTEX-B

• Intercontinental Chemical Transport Experiment - Phase B– April/May 2006

• Study influx of Asian pollution to North America

• Canadian Instrumentation:– Cessna 207 Aircraft (Leaitch)

• 33 Flights• AMS, O3, CO

– Lidar (Duck)– Whistler Peak Measurements

(MacDonald)• AMS, O3, CO, Filter Pack

GEOS-Chem successfully represents Cessna SO4

= over Whistler• Aerosol size limit not present in

GEOS-Chem– Scale AMS SO4

= by average MOUDI impactor size factor (~1.4)

– No scaling applied to organics or nitrate

– Mean GEOS-Chem SO4= bias of

+0.17 ug/m3

From Rupakheti et al., 2005

G-C (dotted)Cessna (solid)

SulfateOrganicsNitrate

GEOS-Chem biased compared to DC-8 SO4=

• Different sampling times and size cutoffs– Filter Pack

• long sample• ~4 um cutoff• GC mean

bias of +0.57 [ug/m3]

– Mist Chamber• 1 min. sample• ~1 um cutoff• GC mean

bias of +0.75 [ug/m3]

• Filter Pack vs. Mist Chamber

– 32% increase in mean model bias

– role of size cutoff?

Averaged between 700 and 900 mb, filtered as Hudman et al., in press• GEOS-Chem mean bias of ~+4 ppt

SO2 measurements are well-captured above 900 mbD

C-

8G

EO

S-

Che

m

Pre

ssur

e [m

b]

SO2 [ppt]

SO

2 [pp

t]

GEOS-Chem SO2 columns low relative to OMI

SO2 [DU]

OM

I

GE

OS

-Ch

em

SO

2 [

DU

]

Sulfate is a large component of AOD

• As noted by Heald et al., 2006, GEOS-Chem total AOD over pacific is low during spring

• AOD bias may represent underestimate in SO2 emissions or effects related to assumed size distribution

GE

OS

-Ch

emM

OD

IS

AO

D

GE

OS

-Ch

em

% A

OD

fro

m

SO

4=

AO

D

MODISGEOS-Chem

Influence of Asian sulfate on Canada

SO

4=

600

mb

Alti

tud

e[k

m]

Alti

tud

e[k

m]

SO

4= [

ug/m

3]

% A

sian

SO

4=

• Significant portion of SO4

= over western Canada is of southeast Asian origin

• Eastern pollution largely north American sources

• Sulfur typically transported as SO4

=

QuestionsThis research has been produced by the collaborative efforts

of:

Randall MartinDalhousie University / Harvard-Smithsonian Center for Astrophysics

Thomas WalkerDalhousie University

Richard Leaitch, Anne Marie Macdonald, and Peter LiuEnvironment Canada

Nickolay KrotkovGoddard Earth Sciences and Technology Center

Jack DibbUniversity of New Hampshire

Greg HueyGeorgia Institute of Technology

This work was supported by the National Sciences and Engineering Research Council of Canada Special Research Opportunity program.

References

• Brock, C., A., P. K. Hudson, E. R. Lovejoy, A. Sullivan, J. B. Nowak, L. G. Huey, O. R. Cooper, D. J. Cziczo, J. de Gouw, F. C. Fehsenfeld, J. S. Holloway, G. Hübler, B. G. Lafleur, D. M. Murphy, J. A. Neuman, D. K. Nicks, D. A. Orsini, D. D. Parish, T. B. Ryerson, D. J. Tanner, C. Varneke, R. J. Weber, and J. C. Wilson, Particle characteristics following cloud-modified transport from Asia to North America. Journal of Geophysical Research, 109, D23S26, doi: 10.1029/2003JD004198, 2004.

• Heald, C. L., D. J. Jacob, R. J. Park, B. Alexander, T. D. Fairlie, R. M. Yantosca, and D. A. Chu, Transpacific transport of Asian anthropogenic aerosols and its impact on surface air quality in the United States. Journal of Geophysical Research, 111, D14310, doi:10.1029/2005JD006847, 2006.

• Hudman, R. C., D. J. Jacob, S. Turquety, E. M. Leibensperger, L. T. Murray, S. Wu, A. B. Gilliland, M. Avery, T. H. Bertram, W. Brune, R. C. Cohen, J. E. Dibb, F. M. Flocke, A. Fried, J. Holloway, J. A. Neumann, R. Orville, A. Perring, X. Ren, G. W. Sachse, H. B. Singh, A. Swanson, P. J. Wooldridge, Surface and lightning sources of nitrogen oxides over the United States: magnitudes, chemical evolution, and outflow. Journal of Geophysical Research, in press.

• Rupakheti, M., R. W. Leaitch, U. Lohmann, K. Hayden, P. Brickell, G. Lu, S.-M. Li, D. Toom-Sauntry, J. W. Bottenheim, J. R. Brook, R. Vet, J. T. Jayne, and D. R. Worsnop, An intensive study of the size and composition of submicron atmospheric aerosols at a rural site in Ontario, Canada. Aerosol Science and Technology, 39, 722-736, 2005.