improved representation of boreal fire emissions for the icartt period s. turquety, d. j. jacob, j....
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Improved representation of boreal fire emissions for the Improved representation of boreal fire emissions for the ICARTT periodICARTT period
S. Turquety, D. J. Jacob, J. A. Logan, R. M. Yevich, R. C. Hudman, F. Y. Leung, S. Turquety, D. J. Jacob, J. A. Logan, R. M. Yevich, R. C. Hudman, F. Y. Leung, R. M. Yantosca, C. L. Heald, L. K. Emmons, D. P. Edwards, R. M. Yantosca, C. L. Heald, L. K. Emmons, D. P. Edwards,
and the INTEX Science Teamand the INTEX Science Team
Burning in boreal forests of Canada or Siberia can have a large impact on an hemispheric scale, and on air quality in the US
Burning in boreal regions expected to increase as a result of climate change
2004 fire season in North America: • worst fire season in Alaska on record! :
2.6 million hectares burned, > 8 x 10-year average• 15 x average area burned in Yukon Territory (60% of national total)• 6 x average in British Columbia
Solène Turquety ([email protected]) – ICARTT Meeting August 10, 2005
US National Interagency Fire Center Canadian Interagency Forest Fire Center
Strong perturbation from the 2004 Alaskan and Canadian firesStrong perturbation from the 2004 Alaskan and Canadian fires
Solène Turquety ([email protected]) – ICARTT Meeting August 10, 2005
Strong signatures in the ICARTT observationsPfister et al., 2005 : 30 ± 5 Tg CO from the fires based on a MOPITT top-down analysisNorth American anthropogenic emissions: 26.5 Tg CO (US: EPA NEI 99, Canada: GEIA scaled to 1998 using CO2 trends)
AIRS/Aqua total CO 18/07/2004
MOPITT total CO 16-18/07/2004
TOMS Aerosol Index 18/07/2004
DC8 flight 18/07/2004
CO DACOM (G. W. Sachse)
Daily variability of the area burned in North America during the summer 2004 Daily variability of the area burned in North America during the summer 2004
Solène Turquety ([email protected]) – ICARTT Meeting August 10, 2005
Location of the fires: MODIS hotspot detection
Temporal variability: daily reports from the U.S. National Interagency Fire Center
Alaska-Yukon [165-125W] North-Central Canada [125-90W]
Day since 20040601 Day since 20040601
Solène Turquety ([email protected]) – ICARTT Meeting August 10, 2005
Fuel loadings:
×
=
Include contribution from peat burningAbove ground only
Potential emissions per unit area Potential emissions per unit area
Derive emissions for 10 species, with 1x1 horizontal resolution: NOx, CO, lumped >= C4 alkanes, lumped >= C3 alkenes, acetone, methyl ethyl ketone, acetaldehyde, propane, formaldehyde, and ethane.
Fraction of peat x 64 tons DM / hectare
Emission factors CO:
Potential emission CO / hectare burned:
Fraction of peat x 0.239 tons CO/ tons DM
CO emissions, summer 2004 – Above ground burning only
Solène Turquety ([email protected]) – ICARTT Meeting August 10, 2005
20.9 Tg CO emitted only considering above ground burning, increase to 31.5 Tg CO if peat burning is included (Yevich and Logan climatology : 9 Tg CO)
Pfister et al., 2005 : 30 ± 5 Tg CO based on MOPITT top-down analysis
Climatological emissions Yevich and Logan2004 fire season, above ground burning only 2004 fire season, including peat burning
Variability – Alaska-Yukon [165-125W]
CO emissions, summer 2004 – Contribution from peat burning
Daily inventory of the 2004 biomass burning emissions Daily inventory of the 2004 biomass burning emissions
Importance of injection heightImportance of injection height
Solène Turquety ([email protected]) – ICARTT Meeting August 10, 2005
Variability max TOMS AI – Alaska-Yukon [165-125W]
TOMS AI depends on both optical depth and altitude of the aerosol plume
Peaks in TOMS AI suggest “pyro-convection” events: end of June, beginning of July, mid-July and mid-August
Average vertical distribution of boreal fires emissions in the CTM:
• 40% boundary layer• 55% FT ~ [600–400hPa]• 5% UT ~ [400–200hPa]
Consistency with atmospheric observations of CO Consistency with atmospheric observations of CO
Solène Turquety ([email protected]) – ICARTT Meeting August 10, 2005
MOPITT Total CO Summer 2004
GEOS-Chem Total CO x MOPITT AK
BB incl. peat
(MOPITT – GOES-Chem)/MOPITT
BB above ground Including the contribution of peat
burning in Alaska and Canada improves comparisons
Distribution of peat uncertain
Fuel and consumption factors associated with peat burning uncertain
CO emissions, summer 2004 – Contribution from peat burning
Consistency with atmospheric observations of CO Consistency with atmospheric observations of CO
Solène Turquety ([email protected]) – ICARTT Meeting August 10, 2005
MOPITTGEOS-Chem – BB above ground onlyGEOS-Chem – Incl. peat burning
Including the contribution of peat burning in Alaska and Canada improves comparisons
Overestimate emissions in Alaska in July
Contribution of peat overestimated in July / underestimated in August?
Expect more important peat burning efficiency later in the fire season
Consistency with atmospheric observations of CO Consistency with atmospheric observations of CO
Solène Turquety ([email protected]) – ICARTT Meeting August 10, 2005
Sensitivity to injection heights - July 17-19, 2004
Strong sensitivity of comparisons between model and MOPITT observations to altitude of injection
Magnitude of the emissions and injection height need to be considered in parallel
Injection in the upper troposphere limited to explosive convection events : introduce time-varying injection heights
MOPITT Total CO GEOS-Chem Total CO – BB 100% BL
GEOS-Chem Total CO – BB 40% BL + 55% FT + 5% UT
GEOS-Chem Total CO – BB 30% BL + 40% FT + 30% UT
Solène Turquety ([email protected]) – ICARTT Meeting August 10, 2005
Consistency with ICARTT observations of CO Consistency with ICARTT observations of CO
DC8 CO observations (DACOM, Glen W. Sachse)Average over the whole mission
P3 CO observations (John Holloway NOAA AL )Average over the whole mission
12km
Simulation overestimate CO below 3km: attributed to an overestimate of the US anthropogenic emissions
Low sensitivity to BB emissions in the average profiles
7kmObservationsGEOS-Chem
(BB above ground only)GEOS-Chem
(BB incl. peat burning)
MeanMedian
Solène Turquety ([email protected]) – ICARTT Meeting August 10, 2005
Summary – Future workSummary – Future work
5 million hectares burned in North America during the summer 2004: 2.3 million hectares in Alaska, 2.5 million hectares in Canada (~1.5 million in Yukon Territory)
31.5 Tg CO emitted, 10 Tg CO corresponding to the contribution from peat burning (close to the 30 ± 5 Tg CO from MOPITT top-down analysis of Pfister et al., 2005)
Comparisons with MOPITT suggests an overestimate of the emissions in Alaska-Yukon in July
TOMS AI suggest that strong pyro-convective events could have occurred, injecting particles and trace gases into the free to upper troposphere
Injection height must be considered in parallel in order to evaluate the impact of forest fire emissions on chemical composition of the troposphere
Use atmospheric observations to improve our representation of the boreal fire emissions using inverse modeling techniques
