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| Titel |
Airborne measurements of CO2, CH4 and HCN in boreal biomass burning plumes |
| VerfasserIn |
Sebastian O'Shea, Stephane Bauguitte, Jennifer B. A. Muller, Michael Le Breton, Alex Archibald, Martin W. Gallagher, Grant Allen, Carl J. Percival |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250074447
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| Zusammenfassung |
| Biomass burning plays an important role in the budgets of a variety of atmospheric trace
gases and particles. For example, fires in boreal Russia have been linked with large growths
in the global concentrations of trace gases such as CO2, CH4 and CO (Langenfelds et al.,
2002; Simpson et al., 2006). High resolution airborne measurements of CO2, CH4 and
HCN were made over Eastern Canada onboard the UK Atmospheric Research Aircraft
FAAM BAe-146 from 12 July to 4 August 2011. These observations were made as part of the
BORTAS project (Quantifying the impact of BOReal forest fires on Tropospheric oxidants
over the Atlantic using Aircraft and Satellites). Flights were aimed at transecting
and sampling the outflow from the commonly occurring North American boreal
forest fires during the summer months and to investigate and identify the chemical
composition and evolution of these plumes. CO2 and CH4 dry air mole fractions were
determined using an adapted system based on a Fast Greenhouse Gas Analyser
(FGGA, Model RMT-200) from Los Gatos Research Inc, which uses the cavity
enhanced absorption spectroscopy technique. In-flight calibrations revealed a mean
accuracy of 0.57Â ppmv and 2.31Â ppbv for 1Â Hz observations of CO2 and CH4,
respectively, during the BORTAS project. During these flights a number of fresh and
photochemically-aged plumes were identified using simultaneous HCN measurements.
HCN is a distinctive and useful marker for forest fire emissions and it was detected
using chemical ionisation mass spectrometry (CIMS). In the freshest plumes, strong
relationships were found between CH4, CO2 and other tracers for biomass burning.
From this we were able to estimate that 8.5 ± 0.9Â g of CH4 and 1512 ± 185Â g of
CO2 were released into the atmosphere per kg of dry matter burnt. These emission
factors are in good agreement with estimates from previous studies and can be
used to calculate budgets for the region. However for aged plumes the correlations
between CH4 and other biomass burning tracers were not as robust, most likely due to
mixing from other CH4 emission sources, such as the wetland regions. The role of
additional emission sources will be investigated using the UK Met Office NAME
atmospheric dispersion model and the HYSPLIT trajectory model. Using tailored
back trajectory analysis, we will present an interpretation of this new dataset in
the context of air mass/fire origin, relating this to MODIS fire maps and source
strength.
Langenfelds et al.: Interannual growth rate variations of atmospheric CO2 and its δ13C,
H2, CH4, and CO between 1992 and 1999 linked to biomass burning, Global Biogeochem.
Cycles, 16, 1048, 2002.
Simpson et al.: Influence of biomass burning during recent fluctuations in the slow
growth of global tropospheric methane, Geophysical Research Letters, 33, L22808,
2006. |
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