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Effects of climate change on forest fires over North America and impact on U.S. air quality and visibility Rynda Hudman, Dominick Spracklen , Jennifer Logan, Loretta Mickley, Shiliang Wu, Rose Yevich Mike Flannigan, Tony Westerling Aerosols…
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impact on U.S. air quality and visibility
Rynda Hudman, Dominick Spracklen,
Jennifer Logan, Loretta Mickley, Shiliang Wu,
Mike Flannigan, Tony Westerling
Organic Carbon (OC) contribution to W. United States fine aerosol:
40% in low fire years
55% in high fire years.
Mean summertime OC emissions over the Western United States 1980 – 2004 used in GEOS-Chem Model
Biofuel & fossil fuel
[Park et al., 2003; Spracklen et al., 2007]
Ozone is generally limited by the supply of NOx
Summertime NOx emissions over lower United States July 1 – August 15 2004 (ICARTT)
1.33 Tg NO
0.04 Tg NO
0.02 Tg NO
0.58 Tg NO
0.26 Tg NO
[Hudman et al., 2007a]
PRESENT DAY EFFECTS OF WILDFIRES ON ATMOSPHERIC CONCENTRATIONS
IMPROVE sites W of 100oW
Simulated July 2004 ozone enhancement
from NA biomass burning 0-2 km
[Spracklen et al., 2007]
[Hudman et al., 2007b]
Interannual variability in summertime OC driven by wildfires.
Wildfires can have hemispheric scale effects on surface ozone
GISS GCM METEROLOGOICAL OUTPUT USED TO PROJECT FUTURE EMISSIONS AND AIR QUALITY CHANGES
changing greenhouse gases (A1B scenario)
GISS general circulation model
1950 2000 2025 2050 2075 2100
Area Burned Regressions
archived met fields
Global chemistry model
Predict Area Burned
Predicted change to summertime (June-Aug) Organic Carbon concentrations over the US
Future / current
Summertime OC concentrations predicted to increase by 25-50% over much of the western US.
[Spracklen et al., in preparation]
PREDICTED AFTERNOON (1-5pm) JULY MEAN OZONE INCREASE DUE TO WESTERN U.S. BIOMASS EMISSIONS 3-6 PPBV*
Biomass burning NOx emissions
Mean of 5 ppbv
to fires a > 2 SD
* note: Changes due to climate change alone have been subtracted out
In terms of air quality 3-6 ppbv means a lot in the summer…..
U.S 8-hr AQS
Courtesy of Dan Jaffe, University of Washington
“The A1 scenario family further distinguishes three sub-scenarios (A1FI, A1T, A1B) by technological emphasis. These scenarios have been extensively applied for climate change projections using general circulation models (GCMs) [IPCC 2001, 2007]. All scenarios project a global increase of anthropogenic emissions of ozone precursors for 2000-2050, largely driven by economic growth in developing countries, but most project decreasing emissions in OECD countries including the United States.
CO2 reaches 522 ppm 2050 in A1B scenario”
[Extracted from Wu et al., 2007a]
Extratropical Forests (b)
NO CO ALK4(C) ACET MEK(C) ALD2(C) PRPE(C) C3H8 CH2O C2H6 SO2 NH3 BC(C) OC(C)
3.00E+00 1.07E+02 3.20E-01 6.00E-01 9.00E-01 6.70E-01 1.00E+00 2.50E-01 2.20E+00 6.00E-01 1.00E+00 1.40E+00 5.60E-01 9.70E+00
From...Andrae and Merlet recent updates (personal communication via J. Logan)
Park, R. J., D. J. Jacob, M. Chin and R. V. Martin, Sources of carbonaceous aerosols over the United States and implications for natural visibility, J. Geophys. Res., 108(D12), 4355, doi:10.1029/2002JD003190, 2003.
Westerling, A., A. Gershunov, T. Brown, D. Cayan, and M. Dettinger (2003), Climate and wildfire in the western united states, Bulletin of the American Meteorological Society, 84 (5), 595-604.
Flannigan, M., K. Logan, B. Amiro, W. Skinner, and B. Stocks (2005), Future area
burned in Canada, Climatic Change, 72 (1-2), 1-16.
Hudman, R. C., et al. (2007), Surface and lightning sources of nitrogen oxides over the United States: magnitudes, chemical evolution, and outflow, J. Geophys. Res., 112, D12S05, doi:10.1029/2006JD007912.
Wu, S., L.J. Mickley, D.J. Jacob, J.A. Logan, R.M. Yantosca, and D. Rind (2007), Why are there large differences between models in global budgets of tropospheric ozone?, J. Geophys. Res., 112, D05302, doi:10.1029/2006JD007801.
Spracklen, D. V., J. A. Logan, L. J. Mickley, R. J. Park, R. Yevich, A. L. Westerling, and D. Jaffe (2007), Wildfires drive interannual variability of organic carbon aerosol in the western U.S. in summer, Geophys. Res. Lett., 34, L16816, doi:10.0129/GL030037.