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| Titel |
Flight-based chemical characterization of biomass burning aerosols within two prescribed burn smoke plumes |
| VerfasserIn |
K. A. Pratt, S. M. Murphy, R. Subramanian, P. J. DeMott, G. L. Kok, T. Campos, D. C. Rogers, A. J. Prenni, A. J. Heymsfield, J. H. Seinfeld, K. A. Prather |
| 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 ; 11, no. 24 ; Nr. 11, no. 24 (2011-12-15), S.12549-12565 |
| Datensatznummer |
250010264
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| Publikation (Nr.) |
 copernicus.org/acp-11-12549-2011.pdf |
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| Zusammenfassung |
| Biomass burning represents a major global source of aerosols impacting direct
radiative forcing and cloud properties. Thus, the goal of a number of current
studies involves developing a better understanding of how the chemical
composition and mixing state of biomass burning aerosols evolve during
atmospheric aging processes. During the Ice in Clouds Experiment-Layer Clouds
(ICE-L) in the fall of 2007, smoke plumes from two small Wyoming Bureau of Land
Management prescribed burns were measured by on-line aerosol instrumentation
aboard a C-130 aircraft, providing a detailed chemical characterization of
the particles. After ~2–4 min of aging, submicron smoke particles,
produced primarily from sagebrush combustion, consisted predominantly of
organics by mass, but were comprised primarily of internal mixtures of
organic carbon, elemental carbon, potassium chloride, and potassium sulfate.
Significantly, the fresh biomass burning particles contained
minor mass fractions of nitrate and sulfate, suggesting that hygroscopic
material is incorporated very near or at the point of emission. The mass
fractions of ammonium, sulfate, and nitrate increased with aging up to
~81–88 min and resulted in acidic particles. Decreasing black carbon mass concentrations
occurred due to dilution of the plume. Increases in the fraction of
oxygenated organic carbon and the presence of dicarboxylic acids, in
particular, were observed with aging. Cloud condensation nuclei measurements
suggested all particles >100 nm were active at 0.5% water
supersaturation in the smoke plumes, confirming the relatively high
hygroscopicity of the freshly emitted particles. For immersion/condensation
freezing, ice nuclei measurements at −32 °C suggested activation
of ~0.03–0.07% of the particles with diameters greater than
500 nm. |
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