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Titel |
The sensitivity of CO and aerosol transport to the temporal and vertical distribution of North American boreal fire emissions |
VerfasserIn |
Y. Chen, Q. Li, J. T. Randerson, E. A. Lyons, R. A. Kahn, D. L. Nelson, D. J. Diner |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1680-7316
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Chemistry and Physics ; 9, no. 17 ; Nr. 9, no. 17 (2009-09-10), S.6559-6580 |
Datensatznummer |
250007619
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Publikation (Nr.) |
copernicus.org/acp-9-6559-2009.pdf |
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Zusammenfassung |
Forest fires in Alaska and western Canada represent
important sources of aerosols and trace gases in North America. Among the
largest uncertainties when modeling forest fire effects are the timing and
injection height of biomass burning emissions. Here we simulate CO and
aerosols over North America during the 2004 fire season, using the GEOS-Chem
chemical transport model. We apply different temporal distributions and
injection height profiles to the biomass burning emissions, and compare
model results with satellite-, aircraft-, and ground-based measurements. We
find that averaged over the fire season, the use of finer temporal resolved
biomass burning emissions usually decreases CO and aerosol concentrations
near the fire source region, and often enhances long-range transport. Among
the individual temporal constraints, switching from monthly to 8-day time
intervals for emissions has the largest effect on CO and aerosol
distributions, and shows better agreement with measured day-to-day
variability. Injection height substantially modifies the surface
concentrations and vertical profiles of pollutants near the source region.
Compared with CO, the simulation of black carbon aerosol is more sensitive
to the temporal and injection height distribution of emissions. The use of
MISR-derived injection heights improves agreement with surface aerosol
measurements near the fire source. Our results indicate that the
discrepancies between model simulations and MOPITT CO measurements near the
Hudson Bay can not be attributed solely to the representation of injection
height within the model. Frequent occurrence of strong convection in North
America during summer tends to limit the influence of injection height
parameterizations of fire emissions in Alaska and western Canada with
respect to CO and aerosol distributions over eastern North America. |
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