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| Titel |
Physiochemical characterisation of biomass burning plumes in Brazil during SAMBBA |
| VerfasserIn |
William Morgan, James Allan, Michael Flynn, Eoghan Darbyshire, Amy Hodgson, Ben Johnson, Jim Haywood, Karla Longo, Paulo Artaxo, Hugh Coe |
| 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 |
250081088
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| Zusammenfassung |
| Biomass burning represents one of the largest sources of particulate matter to the atmosphere,
which results in a significant perturbation to the Earth’s radiative balance coupled with
serious negative impacts on public health. Globally, biomass burning aerosols are thought to
exert a small warming effect of 0.03 Wm-2, however the uncertainty is 4 times greater than
the central estimate. On regional scales, the impact is substantially greater, particularly in
areas such as the Amazon Basin where large, intense and frequent burning occurs on an
annual basis for several months (usually from August-October). Furthermore, a growing
number of people live within the Amazon region, which means that they are subject to the
deleterious effects on their health from exposure to substantial volumes of polluted
air.
Results are presented here from the South American Biomass Burning Analysis
(SAMBBA), which took place during September and October 2012 over Brazil. A suite of
instrumentation was flown on-board the UK Facility for Airborne Atmospheric Measurement
(FAAM) BAe-146 research aircraft. Measurements from the Aerodyne Aerosol Mass
Spectrometer (AMS) and Single Particle Soot Photometer (SP2) form the major part of the
analysis presented here.
The aircraft sampled several fires in close proximity (approximately 150m above the most
intense fires) in different areas of Brazil. This included two extensive areas of burning, which
occurred in the states of Rondonia and Tocantins. The Rondonia fire was largely
dominated by smouldering combustion of a huge single area of rainforest with a
visible plume of smoke extending approximately 80km downwind. The Tocantins
example contrasted with this as it was a collection of a large number of smaller
fires, with flaming combustion being more prevalent. Furthermore, the burned area
was largely made up of agricultural land in a cerrado (savannah-like) region of
Brazil.
Initial results suggest that the chemical nature of these fires differed markedly, with BC
concentrations being an order of magnitude greater in the Tocantins case (up to 50 μg m-3 of
BC) compared with the Rondonia case (up to 5 μg m-3 of BC). Organic matter (OM)
concentrations were similar in both cases, with maximum concentrations peaking between
4-5 mg m-3. Such concentrations are approximately more than 100 times greater than those
sampled in the “background” regional haze. This variation of BC to OM ratio has potentially
large implications for the radiative balance in the respective regions, as BC represents
the major absorbing component of biomass burning aerosol. Further analysis will
compare the aerosol mass concentrations with gas phase species, as well as probing
the chemical and physical evolution of the aerosol as it advects downwind and is
diluted with regional air. In particular, such analyses will focus upon the aging
of the organic aerosol component as well as examining how the mixing state of
the BC particles evolves. Such properties have important implications for the life
cycle and formation of particulate material, which governs its subsequent impacts. |
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