scholarly journals Biomass burning emissions in north Australia during the early dry season: an overview of the 2014 SAFIRED campaign

2016 ◽  
Author(s):  
Marc D. Mallet ◽  
Maximilien J. Desservettaz ◽  
Branka Miljevic ◽  
Andelija Milic ◽  
Zoran D. Ristovski ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Meteorological Data ◽  
Sampling Site ◽  
Northern Region ◽  
Dry Season ◽  
Tropical Region ◽  
Research Station ◽  
Gaseous Emissions ◽  
Biomass Burning Aerosol ◽  
Physical And Chemical

Abstract. The SAFIRED (Savannah Fires in the Early Dry Season) campaign took place from 29th of May, 2014 until the 30th June, 2014 at the Australian Tropical Atmospheric Research Station (ATARS) in the Northern Territory, Australia. The purpose of this campaign was to investigate emissions from fires in the early dry season in northern Australia. Measurements were made of biomass burning aerosols, volatile organic compounds, polycyclic aromatic carbons, greenhouse gases, radon, mercury cycle, and trace metals. Aspects of the biomass burning aerosol emissions investigated included; emission factors of various emitted species, physical and chemical aerosol properties, aerosol aging, micronutrient supply to the ocean, nucleation, and aerosol water uptake. Over the course of the month-long campaign, biomass burning signals were prevalent and emissions from several large single burning events were observed at ATARS. Biomass burning emissions dominated the gas and aerosol concentrations in this region. Nine major biomass burning events were identified and associated with intense or close individual smoke plumes. Dry season fires are extremely frequent and widespread across the northern region of Australia, which suggests that the measured aerosol and gaseous emissions at ATARS are likely representative of signals across the entire region of north Australia. Air mass forward trajectories show that these biomass burning emissions are carried north west over the Timor Sea and could influence the atmosphere over Indonesia and the tropical atmosphere over the Indian Ocean. The outcomes of this campaign will be numerous. This region is an environment with little human impact and provides a unique look into the characteristics of biomass burning aerosol without the influence of other significant emission sources. Relationships between the aerosol physical and chemical properties, gas concentrations and meteorological data for the entire month will provide fundamental knowledge required to understand the influence of early dry season burning in this tropical region on the atmosphere. In this paper we present characteristics of the biomass burning observed at the sampling site and provide an overview of the more specific outcomes of the SAFIRED campaign.

scholarly journals Biomass burning emissions in north Australia during the early dry season: an overview of the 2014 SAFIRED campaign

2017 ◽  
Vol 17 (22) ◽  
pp. 13681-13697 ◽  
Author(s):  
Marc D. Mallet ◽  
Maximilien J. Desservettaz ◽  
Branka Miljevic ◽  
Andelija Milic ◽  
Zoran D. Ristovski ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Sampling Site ◽  
Northern Region ◽  
Dry Season ◽  
Atmospheric Mercury ◽  
Research Station ◽  
Gaseous Emissions ◽  
North West ◽  
Polycyclic Aromatic ◽  
Physical And Chemical

Abstract. The SAFIRED (Savannah Fires in the Early Dry Season) campaign took place from 29 May until 30 June 2014 at the Australian Tropical Atmospheric Research Station (ATARS) in the Northern Territory, Australia. The purpose of this campaign was to investigate emissions from fires in the early dry season in northern Australia. Measurements were made of biomass burning aerosols, volatile organic compounds, polycyclic aromatic carbons, greenhouse gases, radon, speciated atmospheric mercury and trace metals. Aspects of the biomass burning aerosol emissions investigated included; emission factors of various species, physical and chemical aerosol properties, aerosol aging, micronutrient supply to the ocean, nucleation, and aerosol water uptake. Over the course of the month-long campaign, biomass burning signals were prevalent and emissions from several large single burning events were observed at ATARS.Biomass burning emissions dominated the gas and aerosol concentrations in this region. Dry season fires are extremely frequent and widespread across the northern region of Australia, which suggests that the measured aerosol and gaseous emissions at ATARS are likely representative of signals across the entire region of north Australia. Air mass forward trajectories show that these biomass burning emissions are carried north-west over the Timor Sea and could influence the atmosphere over Indonesia and the tropical atmosphere over the Indian Ocean. Here we present characteristics of the biomass burning observed at the sampling site and provide an overview of the more specific outcomes of the SAFIRED campaign.

scholarly journals Composition, size and cloud condensation nuclei activity of biomass burning aerosol from north Australian savannah fires

2016 ◽  
Author(s):  
Marc D. Mallet ◽  
Luke T. Cravigan ◽  
Andelija Milic ◽  
Joel Alroe ◽  
Zoran D. Ristovski ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Cloud Condensation Nuclei ◽  
Chemical Properties ◽  
Dry Season ◽  
Photochemical Oxidation ◽  
Research Station ◽  
Hygroscopic Growth ◽  
Condensation Nuclei ◽  
Trade Winds ◽  
Biomass Burning Aerosol

Abstract. The vast majority of Australia's fires occur in the tropical north of the continent during the dry season. These fires are a significant source of aerosol and cloud condensation nuclei (CCN) in the region, providing a unique opportunity to investigate the biomass burning aerosol (BBA) in the absence of other sources. CCN concentrations at 0.5 % supersaturation and aerosol size and chemical properties were measured at the Australian Tropical Atmospheric Research Station (ATARS) during June 2014. CCN concentrations reached over 104 cm−3 when frequent and close fires were burning; up to 45 times higher than periods with no fires. Both the size distribution and composition of BBA appeared to significantly influence CCN concentrations. A distinct diurnal trend in the proportion of BBA activating to cloud droplets was observed, with an activation ratio of 40 % ± 20 % during the night and 60 % ± 20 % during the day. BBA was, on average, less hygroscopic during the night (κ = 0.04 ± 0.03) than during the day (κ = 0.07 ± 0.05), with a maximum typically observed just before midday. Size-resolved composition of BBA showed that organics comprised a constant 90 % of the aerosol volume for aerodynamic diameters between 100 nm and 200 nm. The photochemical oxidation of organics led to an increase in the hygroscopic growth and an increase in daytime activation ratios. Modelled CCN concentrations assuming typical continental hygroscopicities produced very large overestimations of up to 200 %. Smaller, but still significant over predictions up to ~100 % were observed using AMS and H-TDMA derived hygroscopicities as well as campaign night and day averages. The largest estimations in every case occurred during the night when the small variations in very weakly hygroscopic species corresponded to large variations in the activation diameters. Trade winds carry the smoke generated from these fires over the Timor Sea where aerosol-cloud interactions are likely to be sensitive to changes in CCN concentrations, perturbing cloud albedo and lifetime. Dry season fires in north Australia are therefore potentially very important in cloud processes in this region.

scholarly journals Composition, size and cloud condensation nuclei activity of biomass burning aerosol from northern Australian savannah fires

2017 ◽  
Vol 17 (5) ◽  
pp. 3605-3617 ◽  
Author(s):  
Marc D. Mallet ◽  
Luke T. Cravigan ◽  
Andelija Milic ◽  
Joel Alroe ◽  
Zoran D. Ristovski ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Cloud Condensation Nuclei ◽  
Chemical Properties ◽  
Dry Season ◽  
Photochemical Oxidation ◽  
Research Station ◽  
Hygroscopic Growth ◽  
Condensation Nuclei ◽  
Trade Winds ◽  
Biomass Burning Aerosol

Abstract. The vast majority of Australia's fires occur in the tropical north of the continent during the dry season. These fires are a significant source of aerosol and cloud condensation nuclei (CCN) in the region, providing a unique opportunity to investigate the biomass burning aerosol (BBA) in the absence of other sources. CCN concentrations at 0.5 % supersaturation and aerosol size and chemical properties were measured at the Australian Tropical Atmospheric Research Station (ATARS) during June 2014. CCN concentrations reached over 104 cm−3 when frequent and close fires were burning – up to 45 times higher than periods with no fires. Both the size distribution and composition of BBA appeared to significantly influence CCN concentrations. A distinct diurnal trend in the proportion of BBA activating to cloud droplets was observed, with an activation ratio of 40 ± 20 % during the night and 60 ± 20 % during the day. BBA was, on average, less hygroscopic during the night (κ = 0. 04 ± 0.03) than during the day (κ =  0.07 ± 0.05), with a maximum typically observed just before midday. Size-resolved composition of BBA showed that organics comprised a constant 90 % of the aerosol volume for aerodynamic diameters between 100 and 200 nm. While this suggests that the photochemical oxidation of organics led to an increase in the hygroscopic growth and an increase in daytime activation ratios, it does not explain the decrease in hygroscopicity after midday. Modelled CCN concentrations assuming typical continental hygroscopicities produced very large overestimations of up to 200 %. Smaller, but still significant, overpredictions up to  ∼  100 % were observed using aerosol mass spectrometer (AMS)- and hygroscopicity tandem differential mobility analyser (H-TDMA)-derived hygroscopicities as well as campaign night and day averages. The largest estimations in every case occurred during the night, when the small variations in very weakly hygroscopic species corresponded to large variations in the activation diameters. Trade winds carry the smoke generated from these fires over the Timor Sea, where aerosol–cloud interactions are likely to be sensitive to changes in CCN concentrations, perturbing cloud albedo and lifetime. Dry season fires in northern Australia are therefore potentially very important in cloud processes in this region.

scholarly journals High-Resolution Biomass Burning Aerosol Transport Simulations in the Tropics

Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 91
Author(s):  
Nurzahziani ◽  
Chinnawat Surussavadee ◽  
Thanchanok Noosook
Keyword(s):  
High Resolution ◽  
Biomass Burning ◽  
Mean Squared Error ◽  
Dry Mass ◽  
Northern Region ◽  
Emission Model ◽  
Aerosol Transport ◽  
Monthly Average ◽  
Biomass Burning Aerosol ◽  
The Tropics

This study evaluates the performance of the Weather Research and Forecasting Model with Chemistry (WRF-Chem) for simulating biomass burning aerosol transport at high resolution in the tropics using two different biomass burning emission inventories. Hourly, daily, and monthly average PM10 dry mass concentrations at 5 km resolution—simulated separately using the Brazilian Biomass Burning Emission Model (WRF-3BEM) and the Fire Inventory from NCAR (WRF-FINN) and their averages (WRF-AVG) for 3 months from February to April—are evaluated, using measurements from ground stations distributed in northern Thailand for 2014 and 2015. Results show that WRF-3BEM agrees well with observations and performs much better than WRF-FINN and WRF-AVG. WRF-3BEM simulations are almost unbiased, while those of WRF-FINN and WRF-AVG are significantly overestimated due to significant overestimates of FINN emissions. WRF-3BEM and the measured monthly average PM10 concentrations for all stations and both years are 89.22 and 87.20 μg m−3, respectively. The root mean squared error of WRF-3BEM simulated monthly average PM10 concentrations is 72.00 and 47.01% less than those of WRF-FINN and WRF-AVG, respectively. The correlation coefficient of WRF-3BEM simulated monthly PM10 concentrations and measurements is 0.89. WRF-3BEM can provide useful biomass burning aerosol transport simulations for the northern region of Thailand.

New insights into physical and chemical atmospheric transformations of biomass burning aerosol from wildfires in Siberia

2020 ◽  
Author(s):  
Igor Konovalov ◽  
Nikolai Golovushkin ◽  
Matthias Beekmann ◽  
Valerii Kozlov
Keyword(s):  
Biomass Burning ◽  
Climate Models ◽  
Organic Aerosol ◽  
Chem Phys ◽  
Satellite Observations ◽  
Northern Eurasia ◽  
Brown Carbon ◽  
Radiative Balance ◽  
Biomass Burning Aerosol ◽  
Physical And Chemical

<p>Wildfires in Siberia are a major source of aerosol in Northern Eurasia. Biomass burning (BB) aerosol can significantly impact the Earth’s radiative balance through absorption and scattering of solar radiation, interactions with clouds and changes of surface albedo due to deposition of black and brown carbon on ice and snow. There is growing evidence that atmospheric aging of BB aerosol can be associated with profound but diverse chemical and physical transformations which, in most cases, are not adequately represented in chemistry-transport and climate models that are widely used in assessments of radiative and climate effects of atmospheric pollutants.</p><p>An idea of this study is to identify changes in the optical properties of aging BB aerosol using absorption and extinction aerosol optical depths (AAOD and AOD) retrieved from the OMI and MODIS satellite observations and to elucidate key processes behind these changes using the Mie-theory-based calculations along with simulations with chemistry-transport and microphysical box models involving representation of the evolution of organic particulate matter within the VBS framework. The study focuses on a major outflow of BB plumes from Siberia into the European part of Russia in July 2016. The analysis of the satellite data is complemented by the original results of biomass burning aerosol aging experiments in a large aerosol chamber. </p><p>The results indicate that the BB aerosol evolution during the first 10-20 hours features strong secondary organic aerosol (SOA) formation resulting in a substantial increase in the particle single scattering albedo. Further evolution is affected by the loss of organic matter, probably due to evaporation and oxidation. The results also indicate that although brown carbon contained in the primary aerosol is rapidly lost (consistently with available independent observations) due to evaporation and photochemical destruction of chromospheres, it is partly replaced by weakly absorbing low-volatile SOA.</p><p>In general, this study reveals that aging BB aerosol from wildfires in Siberia undergoes major physical and chemical transformations that have to be taken into account in assessments of the impact of Siberian fires on the radiative balance in Northern Eurasia and the Arctic. It also proposes a practical way to address these complex transformations in chemistry-transport and climate models.</p><p>The study was supported by the Russian Science Foundation (grant agreement No. 19-77-20109).</p><p>References</p><ol><li>Konovalov, I.B., Beekmann, M., Berezin, E.V., Formenti, P., and Andreae, M.O.: Probing into the aging dynamics of biomass burning aerosol by using satellite measurements of aerosol optical depth and carbon monoxide, Atmos. Chem. Phys., 17, 4513–4537, 2017.</li> <li>Konovalov, I.B., Lvova, D.A., Beekmann, M., Jethva, H., Mikhailov, E.F., Paris, J.-D., Belan, B.D., Kozlov, V.S., Ciais, P., and Andreae, M.O.: Estimation of black carbon emissions from Siberian fires using satellite observations of absorption and extinction optical depths, Atmos. Chem. Phys., 18, 14889–14924, 2018.</li> <li>Konovalov, I.B., Beekmann, M., Golovushkin, N.A., and Andreae, M.O.: Nonlinear behavior of organic aerosol in biomass burning plumes: a microphysical model analysis, Atmos. Chem. Phys., 19, 12091–12119, 2019.</li> </ol>

scholarly journals Aging of aerosols emitted from biomass burning in northern Australia

2016 ◽  
Author(s):  
Andelija Milic ◽  
Marc D. Mallet ◽  
Luke T. Cravigan ◽  
Joel Alroe ◽  
Zoran D. Ristovski ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Northern Territory ◽  
Dry Season ◽  
Research Station ◽  
Aerosol Formation ◽  
Chemical Signature ◽  
Aerosol Mass ◽  
Wide Range

Abstract. There is a lack of knowledge of how biomass burning aerosols in the tropics age, including those in the fire-prone Northern Territory in Australia. This paper reports chemical characterization and aging of aerosols monitored during the one month long SAFIRED (Savannah Fires in the Early Dry Season) field study, with an emphasis on chemical signature and aging of organic aerosols. The campaign took place in June 2014 during the early dry season when the surface measurement site, the Australian Tropical Atmospheric Research Station (ATARS), located in the Northern Territory, was heavily influenced by thousands of wild and prescribed bushfires. ATARS was equipped with a wide suite of instrumentation for gaseous and aerosol characterization. A compact time-of-flight aerosol mass spectrometer was deployed to monitor aerosol chemical composition. Approximately 80 % of submicron carbonaceous mass and 90 % of submicron non-refractory mass was composed of organic material. Ozone enhancement in biomass burning plumes indicated increased air mass photochemistry and increased organic aerosol and particle diameter with the aging parameter (f44) suggested secondary organic aerosol formation. Diversity of biomass burning emissions was illustrated through variability in chemical signature (e.g. wide range in f44, from 0.06 to 0.13) for five intense fire events. The background particulate loading was characterized using Positive Matrix Factorization (PMF). A PMF-resolved BBOA (biomass burning organic aerosol) factor comprised 24 % of the submicron non-refractory organic aerosol mass, confirming the significance of fire sources. A dominant PMF factor, OOA (oxygenated organic aerosol), made up 47 % of sampled aerosol fraction, illustrating the importance of aerosol aging in the Northern Territory. Biogenic IEPOX-SOA (isoprene epoxydiols-related secondary organic aerosol) was the third significant fraction of the background aerosol (28 %).

scholarly journals Impact of mixing state and hygroscopicity on CCN activity of biomass burning aerosol in Amazonia

2017 ◽  
Vol 17 (3) ◽  
pp. 2373-2392 ◽  
Author(s):  
Madeleine Sánchez Gácita ◽  
Karla M. Longo ◽  
Julliana L. M. Freire ◽  
Saulo R. Freitas ◽  
Scot T. Martin
Keyword(s):  
Case Studies ◽  
Biomass Burning ◽  
General Circulation ◽  
Dry Season ◽  
Mixing State ◽  
Smoke Particles ◽  
Droplet Concentration ◽  
Biomass Burning Aerosol ◽  
Mixed Populations ◽  
The Times

Abstract. Smoke aerosols prevail throughout Amazonia because of widespread biomass burning during the dry season, and external mixing, low variability in the particle size distribution and low particle hygroscopicity are typical. There can be profound effects on cloud properties. This study uses an adiabatic cloud model to simulate the activation of smoke particles as cloud condensation nuclei (CCN) for three hypothetical case studies, chosen as to resemble biomass burning aerosol observations in Amazonia. The relative importance of variability in hygroscopicity, mixing state, and activation kinetics for the activated fraction and maximum supersaturation is assessed. For a population with κp = 0.04, an overestimation of the cloud droplet number concentration Nd for the three selected case studies between 22.4 ± 1.4 and 54.3 ± 3.7 % was obtained when assuming a hygroscopicity parameter κp = 0.20. Assuming internal mixing of the aerosol population led to overestimations of up to 20 % of Nd when a group of particles with medium hygroscopicity was present in the externally mixed population cases. However, the overestimations were below 10 % for external mixtures between very low and low-hygroscopicity particles, as seems to be the case for Amazon smoke particles. Kinetic limitations were significant for medium- and high-hygroscopicity particles, and much lower for very low and low-hygroscopicity particles. When particles were assumed to be at equilibrium and to respond instantly to changes in the air parcel supersaturation, the overestimation of the droplet concentration was up to  ∼  100 % in internally mixed populations, and up to  ∼  250 % in externally mixed ones, being larger for the higher values of hygroscopicity. In addition, a perceptible delay between the times when maximum supersaturation and maximum aerosol activated fraction are reached was noticed and, for aerosol populations with effective hygroscopicity κpeff higher than a certain threshold value, the delay in particle activation was such that no particles were activated at the time of maximum supersaturation. Considering internally mixed populations, for an updraft velocity W = 0.5 m s−1 this threshold of no activation varied between κpeff = 0.35 and κpeff = 0.5 for the different case studies. However, for low hygroscopicity, kinetic limitations played a weaker role for CCN activation of particles, even when taking into account the large aerosol mass and number concentrations. For the very low range of hygroscopicities, the overestimation of the droplet concentration due to the equilibrium assumption was lowest and the delay between the times when maximum supersaturation and maximum activated fraction were reached was greatly reduced or no longer observed (depending on the case study). These findings on uncertainties and sensitivities provide guidance on appropriate simplifications that can be used for modeling of smoke aerosols within general circulation models. The use of medium values of hygroscopicity representative of smoke aerosols for other biomass burning regions on Earth can lead to significant errors compared to the use of low hygroscopicity for Amazonia (between 0.05 and 0.13, according to available observations). Also in this region, consideration of the biomass burning population as internally mixed will lead to small errors in the droplet concentration, while significantly increasing the computational burden. Regardless of the large smoke aerosol loads in the region during the dry season, kinetic limitations are expected to be low.

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