Influence of plumes from biomass burning on atmospheric chemistry over the equatorial and tropical South Atlantic during CITE 3

Andreae, Meinrat O.; Anderson, B. E.; Blake, D. R.; Bradshaw, J. D.; Collins, J. E.; Gregory, G. L.; Sachse, G. W.; Shipham, M. C.

doi:10.1029/94jd00263

Cited by 184 publications

(116 citation statements)

References 51 publications

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“…As an illustrative example we show the background data from Flight A10 (blue squares). Regression analysis of the data from altitudes <2 km gives a CN/ CO ratio of 17.2 ± 0.3 cm −3 ppb −1 (r 2 = 0.73, N = 1135), similar to previous results in aged smoke, and consistent with some loss of particles by coagulation and other processes during aging (Andreae et al, 1994;Browell et al, 1996). It is difficult to derive regression slopes from the regional data from the northerly flights, but an overall trend similar to the one indicated for the background on A10 may also apply for these data (blue, green and yellow circles on Fig.…”

Section: Barca-a: Late Dry Seasonsupporting

confidence: 88%

Carbon monoxide and related trace gases and aerosols over the Amazon Basin during the wet and dry seasons

Artaxo²,

et al. 2012

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Abstract. We present the results of airborne measurements of carbon monoxide (CO) and aerosol particle number concentration (CN) made during the Balanço Atmosférico Regional de Carbono na Amazônia (BARCA) program. The primary goal of BARCA is to address the question of basinscale sources and sinks of CO 2 and other atmospheric carbon species, a central issue of the Large-scale BiosphereAtmosphere (LBA) program. The experiment consisted of two aircraft campaigns during November-December 2008 (BARCA-A) and May-June 2009 (BARCA-B), which covered the altitude range from the surface up to about 4500 m, and spanned most of the Amazon Basin.Based on meteorological analysis and measurements of the tracer, SF 6 , we found that airmasses over the Amazon Basin during the late dry season (BARCA-A, November 2008) originated predominantly from the Southern Hemisphere, while during the late wet season (BARCA-B, May 2009) low-level airmasses were dominated by northernhemispheric inflow and mid-tropospheric airmasses were of mixed origin. In BARCA-A we found strong influence of biomass burning emissions on the composition of the atmosphere over much of the Amazon Basin, with CO enhancements up to 300 ppb and CN concentrations approaching 10 000 cm −3 ; the highest values were in the southern part of the Basin at altitudes of 1-3 km. The CN/ CO ratios were diagnostic for biomass burning emissions, and were lower in aged than in fresh smoke. Fresh emissions indicated CO/CO 2 and CN/CO emission ratios in good agreement with previous work, but our results also highlight the need to consider the residual smoldering combustion that takes place after the active flaming phase of deforestation fires.During the late wet season, in contrast, there was little evidence for a significant presence of biomass smoke. Low CN concentrations (300-500 cm −3 ) prevailed basinwide, and CO mixing ratios were enhanced by only ∼10 ppb above the mixing line between Northern and Southern Hemisphere air. There was no detectable trend in CO with distance from the coast, but there was a small enhancement of CO in the boundary layer suggesting diffuse biogenic sources from photochemical degradation of biogenic volatile organic compounds or direct biological emission.Simulations of CO distributions during BARCA-A using a range of models yielded general agreement in spatial distribution and confirm the important contribution from biomass burning emissions, but the models evidence some systematic quantitative differences compared to observed CO concentrations. These mismatches appear to be related to problems with the accuracy of the global background fields, the role Published by Copernicus Publications on behalf of the European Geosciences Union. M. O. Andreae et al.: Carbon monoxide and related trace gases and aerosolsof vertical transport and biomass smoke injection height, the choice of model resolution, and reliability and temporal resolution of the emissions data base.

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Section: Barca-a: Late Dry Seasonsupporting

confidence: 88%

Carbon monoxide and related trace gases and aerosols over the Amazon Basin during the wet and dry seasons

Artaxo²,

et al. 2012

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“…The modelled increase is not due to an increase in NO y or O 3 that remains nearly constant, but is due to the strong chemical destruction of CO in these runs. Therefore, in the run with chemistry only, an increase in the O 3 /CO slope is the result of a decrease in CO, and not the result of photochemical O 3 production as is often stated (Andreae et al, 1994;Mauzerall et al, 1998). Along the same lines, Chin et al (1994) showed that a decrease in O 3 /CO slopes could be due to the secondary production of CO by hydrocarbon oxidation in a fresh plume, and not just due to chemical destruction or deposition of O 3 .…”

Section: Trace Gas Correlationsmentioning

confidence: 80%

Lagrangian analysis of low altitude anthropogenic plume processing across the North Atlantic

et al. 2008

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Abstract. The photochemical evolution of an anthropogenic plume from the New-York/Boston region during its transport at low altitudes over the North Atlantic to the European west coast has been studied using a Lagrangian framework. This plume, originally strongly polluted, was sampled by research aircraft just off the North American east coast on 3 successive days, and then 3 days downwind off the west coast of Ireland where another aircraft re-sampled a weakly polluted plume. Changes in trace gas concentrations during transport are reproduced using a photochemical trajectory model including deposition and mixing effects. Chemical and wet deposition processing dominated the evolution of all pollutants in the plume. The mean net photochemical O 3 production is estimated to be −5 ppbv/day leading to low O 3 by the time the plume reached Europe. Model runs with no wet deposition of HNO 3 predicted much lower average net destruction of −1 ppbv/day O 3 , arising from increased levels of NO x via photolysis of HNO 3 . This indicates that wet deposition of HNO 3 is indirectly responsible for 80% of the net destruction of ozone during plume transport. If the plume had not encountered precipitation, it would have reached Europe with Correspondence to: E. Real (elsa.real@aero.jussieu.fr) O 3 concentrations of up to 80 to 90 ppbv and CO between 120 and 140 ppbv. Photochemical destruction also played a more important role than mixing in the evolution of plume CO due to high levels of O 3 and water vapour showing that CO cannot always be used as a tracer for polluted air masses, especially in plumes transported at low altitudes. The results also show that, in this case, an increase in O 3 /CO slopes can be attributed to photochemical destruction of CO and not to photochemical O 3 production as is often assumed.

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“…Over the Atlantic Ocean, it is likely that dust particles are mixed with marine aerosol (sea salt, organic matter and oxidation products of dimethyl sulfide (Yu et al, 2009)) and biomass-burning aerosols from the Sahel region (Andreae et al, 1994;Formenti et al, 2008;Ansmann et al, 2009). This mixing increases the fine fraction, f , defined as the aerosol fraction with diameter smaller than 1 µm (Kaufmann et al, 2005b).…”

Section: Methodsmentioning

confidence: 99%

Transport of North African dust from the Bodélé depression to the Amazon Basin: a case study

Ben-Ami¹,

Koren²,

Rudich³

et al. 2010

Atmos. Chem. Phys.

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Abstract. Through long-range transport of dust, the NorthAfrican desert supplies essential minerals to the Amazon rain forest. Since North African dust reaches South America mostly during the Northern Hemisphere winter, the dust sources active during winter are the main contributors to the forest. Given that the Bodélé depression area in southwestern Chad is the main winter dust source, a close link is expected between the Bodélé emission patterns and volumes and the mineral supply flux to the Amazon.Until now, the particular link between the Bodélé and the Amazon forest was based on sparse satellite measurements and modeling studies. In this study, we combine a detailed analysis of space-borne and ground data with reanalysis model data and surface measurements taken in the central Amazon during the Amazonian Aerosol Characterization Experiment (AMAZE-08) in order to explore the validity and the nature of the proposed link between the Bodélé depression and the Amazon forest.This case study follows the dust events of 11-16 and 18-27 February 2008, from the emission in the Bodélé over West Africa (most likely with contribution from other dust sources in the region) the crossing of the Atlantic Ocean, to the observed effects above the Amazon canopy about 10 days after the emission. The dust was lifted by surface winds stronger than 14 m s −1 , usually starting early in the morning. TheCorrespondence to: Y. Ben-Ami (yuval.ben-ami@weizmann.ac.il) lofted dust, mixed with biomass burning aerosols over Nigeria, was transported over the Atlantic Ocean, and arrived over the South American continent. The top of the aerosol layer reached above 3 km, and the bottom merged with the boundary layer. The arrival of the dusty air parcel over the Amazon forest increased the average concentration of aerosol crustal elements by an order of magnitude.

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Influence of plumes from biomass burning on atmospheric chemistry over the equatorial and tropical South Atlantic during CITE 3

Cited by 184 publications

References 51 publications

Carbon monoxide and related trace gases and aerosols over the Amazon Basin during the wet and dry seasons

Carbon monoxide and related trace gases and aerosols over the Amazon Basin during the wet and dry seasons

Lagrangian analysis of low altitude anthropogenic plume processing across the North Atlantic

Transport of North African dust from the Bodélé depression to the Amazon Basin: a case study

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