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| Titel |
Airborne measurements of trace gas and aerosol particle emissions from biomass burning in Amazonia |
| VerfasserIn |
P. Guyon, G. P. Frank, M. Welling, D. Chand, P. Artaxo, L. Rizzo, G. Nishioka, O. Kolle, H. Fritsch, M. A. F. Silva Dias, L. V. Gatti, A. M. Cordova, M. O. Andreae |
| 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 ; 5, no. 11 ; Nr. 5, no. 11 (2005-11-08), S.2989-3002 |
| Datensatznummer |
250003144
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| Publikation (Nr.) |
 copernicus.org/acp-5-2989-2005.pdf |
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| Zusammenfassung |
| As part of the LBA-SMOCC (Large-Scale Biosphere-Atmosphere Experiment in
Amazonia - Smoke, Aerosols, Clouds, Rainfall, and Climate) 2002 campaign, we
studied the emission of carbon monoxide (CO), carbon dioxide (CO2), and
aerosol particles from Amazonian deforestation fires using an instrumented
aircraft. Emission ratios for aerosol number (CN) relative to CO
(ERCN/CO) fell in the range 14-32 cm-3 ppb-1 in most of the
investigated smoke plumes. Particle number emission ratios have to our
knowledge not been previously measured in tropical deforestation fires, but
our results are in agreement with values usually found from tropical savanna
fires. The number of particles emitted per amount biomass burned was found
to be dependent on the fire conditions (combustion efficiency). Variability
in ERCN/CO between fires was similar to the variability caused by
variations in combustion behavior within each individual fire. This was
confirmed by observations of CO-to-CO2 emission ratios (ERCO/CO2),
which stretched across the same wide range of values for individual fires as
for all the fires observed during the sampling campaign, reflecting the fact
that flaming and smoldering phases are present simultaneously in
deforestation fires. Emission factors (EF) for CO and aerosol particles were
computed and a correction was applied for the residual smoldering combustion
(RSC) fraction of emissions that are not sampled by the aircraft, which
increased the EF by a factor of 1.5-2.1. Vertical transport of smoke from
the boundary layer (BL) to the cloud detrainment layer (CDL) and the free
troposphere (FT) was found to be a very common phenomenon. We observed a
20% loss in particle number as a result of this vertical transport and
subsequent cloud processing, attributable to in-cloud coagulation. This
small loss fraction suggests that this mode of transport is very efficient
in terms of particle numbers and occurs mostly via non-precipitating clouds.
The detrained aerosol particles released in the CDL and FT were larger than
in the unprocessed smoke, mostly due to coagulation and secondary growth,
and therefore more efficient at scattering radiation and nucleating cloud
droplets. This process may have significant atmospheric implications on a
regional and larger scale. |
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