scholarly journals Global-scale constraints on light-absorbing anthropogenic iron oxide aerosols

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
K. D. Lamb ◽  
H. Matsui ◽  
J. M. Katich ◽  
A. E. Perring ◽  
J. R. Spackman ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Black Carbon ◽  
Fossil Fuel ◽  
Global Scale ◽  
Aerosol Model ◽  
Carbon Particles ◽  
Source Regions ◽  
Fossil Fuel Burning ◽  
Light Absorber ◽  
The Pacific

AbstractAnthropogenic iron oxide aerosols (FeOx) have been identified as a climatically significant atmospheric light absorber, and as a contributor of free iron to the oceans. Here we provide global-scale constraints on their atmospheric abundance with measurements over the remote Pacific and Atlantic Oceans from aircraft campaigns spanning 10 years. We find FeOx-like aerosols are transported far from source regions with similar efficiency as black carbon particles. Strong contrast in concentrations was observed between the Northern and Southern Hemisphere Pacific. We provide observational constraints in remote regions on the ambient ratios of FeOx relative to BC from fossil fuel burning. Comparison with a global aerosol model tuned to recent observations in East-Asian source regions confirm an upward revision of emissions based on model/observation comparison over the Pacific receptor region. We find that anthropogenic FeOx-like particles generate global-scale shortwave atmospheric heating 0.3–26% of that of black carbon in remote regions where concentrations of both aerosols are very low.

scholarly journals Global combustion: the connection between fossil fuel and biomass burning emissions (1997–2010)

2016 ◽  
Vol 371 (1696) ◽  
pp. 20150177 ◽  
Author(s):  
Jennifer K. Balch ◽  
R. Chelsea Nagy ◽  
Sally Archibald ◽  
David M. J. S. Bowman ◽  
Max A. Moritz ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Urban Areas ◽  
Fossil Fuel ◽  
Global Scale ◽  
Fossil Fuel Burning ◽  
Annual Carbon ◽  
Global Modelling ◽  
Human Use ◽  
Global Data ◽  
Fossil Fuel Emissions

Humans use combustion for heating and cooking, managing lands, and, more recently, for fuelling the industrial economy. As a shift to fossil-fuel-based energy occurs, we expect that anthropogenic biomass burning in open landscapes will decline as it becomes less fundamental to energy acquisition and livelihoods. Using global data on both fossil fuel and biomass burning emissions, we tested this relationship over a 14 year period (1997–2010). The global average annual carbon emissions from biomass burning during this time were 2.2 Pg C per year (±0.3 s.d.), approximately one-third of fossil fuel emissions over the same period (7.3 Pg C, ±0.8 s.d.). There was a significant inverse relationship between average annual fossil fuel and biomass burning emissions. Fossil fuel emissions explained 8% of the variation in biomass burning emissions at a global scale, but this varied substantially by land cover. For example, fossil fuel burning explained 31% of the variation in biomass burning in woody savannas, but was a non-significant predictor for evergreen needleleaf forests. In the land covers most dominated by human use, croplands and urban areas, fossil fuel emissions were more than 30- and 500-fold greater than biomass burning emissions. This relationship suggests that combustion practices may be shifting from open landscape burning to contained combustion for industrial purposes, and highlights the need to take into account how humans appropriate combustion in global modelling of contemporary fire. Industrialized combustion is not only an important driver of atmospheric change, but also an important driver of landscape change through companion declines in human-started fires. This article is part of the themed issue ‘The interaction of fire and mankind’.

scholarly journals Modeled source apportionment of black carbon particles coated with a light-scattering shell

2020 ◽  
Author(s):  
Aki Virkkula
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Fossil Fuel ◽  
Size Distributions ◽  
Core Size ◽  
Carbon Particles ◽  
Aerosol Mass ◽  
Measured Absorption ◽  
Absorbing Material ◽  
Fossil Fuel Emissions

Abstract. The Aethalometer model been used widely for estimating the contributions of fossil fuel emissions and biomass burning to equivalent black carbon (eBC). The calculation is based on measured absorption Ångström exponents (αabs). The interpretation αabs is ambiguous since it is well-known that it not only depends on the dominant absorber but also on the size and internal structure of the particles, core size and shell thickness. In this work the uncertainties of the Aethalometer-model-derived apparent fractions of absorption by eBC from fossil fuel and biomass burning are evaluated with a core-shell Mie model. Biomass-burning fractions (BB(%)) were calculated for pure and coated single BC particles, for lognormal unimodal and bimodal size distributions of BC cores coated with ammonium sulfate, a scattering-only material. BB(%) was very seldom 0 % even though BC was the only absorbing material in the simulations. The shape of size distribution plays an important role. Narrow size distributions result in higher αabs and BB(%) values than wide size distributions. The sensitivity of αabs and BB(%) to variations in shell volume fractions is the highest for accumulation mode particles. This is important because that is where the largest aerosol mass is. For the interpretation of absorption Ångström exponents it would be very good to measure BC size distributions and shell thicknesses together with the wavelength dependency of absorption.

scholarly journals Long-range transport of black carbon to the Pacific Ocean and its dependence on aging timescale

2015 ◽  
Vol 15 (12) ◽  
pp. 16945-16983 ◽  
Author(s):  
J. Zhang ◽  
J. Liu ◽  
S. Tao ◽  
G. A. Ban-Weiss
Keyword(s):  
Pacific Ocean ◽  
Black Carbon ◽  
Source Region ◽  
Climate Impacts ◽  
Average Lifetime ◽  
Deposition Rates ◽  
Source Regions ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The Impact

Abstract. Improving the ability of global models to predict concentrations of black carbon (BC) over the Pacific Ocean is essential to evaluate the impact of BC on marine climate. In this study, we tag BC tracers from 13 source regions around the globe in a global chemical transport model MOZART-4. Numerous sensitivity simulations are carried out varying the aging timescale of BC emitted from each source region. The aging timescale for each source region is optimized by minimizing errors in vertical profiles of BC mass mixing ratios between simulations and HIAPER Pole-to-Pole Observations (HIPPO). For most HIPPO deployments, in the Northern Hemisphere, optimized aging timescales are less than half a day for BC emitted from tropical and mid-latitude source regions, and about 1 week for BC emitted from high latitude regions in all seasons except summer. We find that East Asian emissions contribute most to the BC loading over the North Pacific, while South American, African and Australian emissions dominate BC loadings over the South Pacific. Dominant source regions contributing to BC loadings in other parts of the globe are also assessed. The lifetime of BC originating from East Asia (i.e., the world's largest BC emitter) is found to be only 2.2 days, much shorter than the global average lifetime of 4.9 days, making East Asia's contribution to global burden only 36 % of BC from the second largest emitter, Africa. Thus, evaluating only relative emission rates without accounting for differences in aging timescales and deposition rates is not predictive of the contribution of a given source region to climate impacts. Our simulations indicate that lifetime of BC increases nearly linearly with aging timescale for all source regions. When aging rate is fast, the lifetime of BC is largely determined by factors that control local deposition rates (e.g. precipitation). The sensitivity of lifetime to aging timescale depends strongly on the initial hygroscopicity of freshly emitted BC. Our findings suggest that the aging timescale of BC varies significantly by region and season, and can strongly influence the contribution of source regions to BC burdens around the globe. Improving parameterizations of the aging process for BC is important for enhancing the predictive skill of air quality and climate models. Future observations that investigate the evolution of hygroscopicity of BC as it ages from different source regions to the remote atmosphere are urgently needed.

scholarly journals Global-scale seasonally resolved black carbon vertical profiles over the Pacific

2013 ◽  
Vol 40 (20) ◽  
pp. 5542-5547 ◽  
Author(s):  
J. P. Schwarz ◽  
B. H. Samset ◽  
A. E. Perring ◽  
J. R. Spackman ◽  
R. S. Gao ◽  
...  
Keyword(s):  
Black Carbon ◽  
Global Scale ◽  
Vertical Profiles ◽  
The Pacific

scholarly journals Sensitivity of global-scale climate change attribution results to inclusion of fossil fuel black carbon aerosol

2005 ◽  
Vol 32 (14) ◽  
pp. n/a-n/a ◽  
Author(s):  
Gareth S. Jones ◽  
Andy Jones ◽  
David L. Roberts ◽  
Peter A. Stott ◽  
Keith D. Williams
Keyword(s):  
Climate Change ◽  
Black Carbon ◽  
Fossil Fuel ◽  
Global Scale ◽  
Black Carbon Aerosol

scholarly journals Long-range transport of black carbon to the Pacific Ocean and its dependence on aging timescale

2015 ◽  
Vol 15 (20) ◽  
pp. 11521-11535 ◽  
Author(s):  
J. Zhang ◽  
J. Liu ◽  
S. Tao ◽  
G. A. Ban-Weiss
Keyword(s):  
Pacific Ocean ◽  
East Asia ◽  
Black Carbon ◽  
Source Region ◽  
Climate Impacts ◽  
Deposition Rates ◽  
Global Models ◽  
Source Regions ◽  
The Pacific ◽  
The Pacific Ocean

Abstract. Improving the ability of global models to predict concentrations of black carbon (BC) over the Pacific Ocean is essential to evaluate the impact of BC on marine climate. In this study, we tag BC tracers from 13 source regions around the globe in a global chemical transport model, Model for Ozone and Related Chemical Tracers, version 4 (MOZART-4). Numerous sensitivity simulations are carried out varying the aging timescale of BC emitted from each source region. The aging timescale for each source region is optimized by minimizing errors in vertical profiles of BC mass mixing ratios between simulations and HIAPER Pole-to-Pole Observations (HIPPO). For most HIPPO deployments, in the Northern Hemisphere, optimized aging timescales are less than half a day for BC emitted from tropical and midlatitude source regions and about 1 week for BC emitted from high-latitude regions in all seasons except summer. We find that East Asian emissions contribute most to the BC loading over the North Pacific, while South American, African and Australian emissions dominate BC loadings over the South Pacific. Dominant source regions contributing to BC loadings in other parts of the globe are also assessed. The lifetime of BC originating from East Asia (i.e., the world's largest BC emitter) is found to be only 2.2 days, much shorter than the global average lifetime of 4.9 days, making the contribution from East Asia to the global BC burden only 36 % of that from the second largest emitter, Africa. Thus, evaluating only relative emission rates without accounting for differences in aging timescales and deposition rates is not predictive of the contribution of a given source region to climate impacts. Our simulations indicate that the lifetime of BC increases nearly linearly with aging timescale for all source regions. When the aging rate is fast, the lifetime of BC is largely determined by factors that control local deposition rates (e.g., precipitation). The sensitivity of lifetime to aging timescale depends strongly on the initial hygroscopicity of freshly emitted BC. Our findings suggest that the aging timescale of BC varies significantly by region and season and can strongly influence the contribution of source regions to BC burdens around the globe. Therefore, improving parameterizations of the aging process for BC is important for enhancing the predictive skill of global models. Future observations that investigate the evolution of the hygroscopicity of BC as it ages from different source regions to the remote atmosphere are urgently needed.

scholarly journals Temporally-Delineated Sources of Major Chemical Species in High Arctic Snow

2017 ◽  
Author(s):  
Katrina M. Macdonald ◽  
Sangeeta Sharma ◽  
Desiree Toom ◽  
Alina Chivulescu ◽  
Andrew Platt ◽  
...  
Keyword(s):  
Black Carbon ◽  
Fossil Fuel ◽  
Major Ions ◽  
Chemical Species ◽  
High Arctic ◽  
The Arctic ◽  
Radiative Balance ◽  
Fossil Fuel Burning ◽  
Major Chemical ◽  
Rich Data

Abstract. Long-range transport of aerosol from lower latitudes to the high Arctic may be a significant contributor to climate forcing in the Arctic. To identify the sources of key contaminants entering the Canadian high Arctic an intensive campaign of snow sampling was completed at Alert, Nunavut, from September 2014 to June 2015. Fresh snow samples collected every few days were analysed for black carbon, major ions, and metals, and this rich data provided an opportunity for a temporally-refined source apportionment of snow composition via Positive Matrix Factorization in conjunction with FLEXPART potential emission sensitivity analysis. Seven source factors were identified: sea salt, regional dust, Eurasian fossil fuel combustion, mixed carboxylic acid sources, nitrate processing, Eurasian industrial activities, and regional volcanic and marine biogenic activity. The majority (73 %) of the black carbon in snow, a light-absorbing compound critical to the Arctic radiative balance, was found to be the product of fossil fuel burning with limited biomass burning influence.

scholarly journals Modeled source apportionment of black carbon particles coated with a light-scattering shell

2021 ◽  
Vol 14 (5) ◽  
pp. 3707-3719
Author(s):  
Aki Virkkula
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Fossil Fuel ◽  
Size Distributions ◽  
Core Size ◽  
Carbon Particles ◽  
Aerosol Mass ◽  
Measured Absorption ◽  
Absorbing Material ◽  
Fossil Fuel Emissions

Abstract. The Aethalometer model has been used widely for estimating the contributions of fossil fuel emissions and biomass burning to equivalent black carbon (eBC). The calculation is based on measured absorption Ångström exponents (αabs). The interpretation of αabs is ambiguous since it is well known that it not only depends on the dominant absorber but also on the size and internal structure of the particles, core size, and shell thickness. In this work the uncertainties of the Aethalometer-model-derived apparent fractions of absorption by eBC from fossil fuel and biomass burning are evaluated with a core–shell Mie model. Biomass-burning fractions (BB(%)) were calculated for pure and coated single BC particles for lognormal unimodal and bimodal size distributions of BC cores coated with ammonium sulfate, a scattering-only material. BB(%) was very seldom 0 % even though BC was the only absorbing material in the simulations. The shape of size distribution plays an important role. Narrow size distributions result in higher αabs and BB(%) values than wide size distributions. The sensitivity of αabs and BB(%) to variations in shell volume fractions is the highest for accumulation-mode particles. This is important because that is where the largest aerosol mass is. For the interpretation of absorption Ångström exponents it would be very good to measure BC size distributions and shell thicknesses together with the wavelength dependency of absorption.

scholarly journals Atmospheric inversion of SO<sub>2</sub> and primary aerosol emissions for the year 2010

2013 ◽  
Vol 13 (3) ◽  
pp. 6165-6218
Author(s):  
N. Huneeus ◽  
O. Boucher ◽  
F. Chevallier
Keyword(s):  
Biomass Burning ◽  
Fossil Fuel ◽  
A Priori ◽  
Regional Scale ◽  
Model Performance ◽  
Global Scale ◽  
Aerosol Model ◽  
Skill Scores ◽  
Emission Fluxes ◽  
Aerosol Emissions

Abstract. Natural and anthropogenic emissions of primary aerosols and sulphur dioxide (SO2) are estimated for the year 2010 by assimilating daily total and fine mode aerosol optical depth (AOD) at 550 nm from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite instrument into a global aerosol model of intermediate complexity. The system adjusts monthly emission fluxes over a set of predefined regions tiling the globe. The resulting aerosol emissions improve the model performance, as measured from usual skill scores, both against the assimilated observations and a set of independent ground-based measurements. The estimated emission fluxes are 67 Tg S yr−1 for SO2, 12 Tg yr−1 for black carbon (BC), 87 Tg yr−1 for particulate organic matter (POM), 17 Pg yr−1 for sea salt (SS, estimated at 80% relative humidity) and 1206 Tg yr−1 for desert dust (DD). They represent a difference of +53%, +73%, +72%, +1% and −8%, respectively, with respect to the first guess (FG) values. Constant errors throughout the regions and the year were assigned to the a priori emissions. The analysis errors are reduced for all species and throughout the year, they vary between 3% and 17% for SO2, 1% and 130% for biomass burning, 25% and 89% for fossil fuel, 1% and 200% for DD and 1% and 5% for SS. The maximum errors on the global-annual scale for the estimated fluxes (considering temporal error dependence) are 12% for SO2, 39% for BC, 41% for POM, 43% for DD and 40% for SS. These values represent a decrease as compared to the global-annual errors from the FG of 12% for SO2, 42% for BC, 47% for POM, 50% for DD and 95% for SS. The largest error reduction, both monthly and yearly, is observed for SS and the smallest one for SO2. The sensitivity and robustness of the inversion system to the choice of the first guess emission inventory is investigated by using different combinations of inventories for industrial, fossil fuel and biomass burning sources. The initial difference in the emissions between the various setups is reduced after the inversion. Furthermore, at the global scale, the inversion is sensitive to the choice of the BB inventory and not so much to the industrial and fossil fuel inventory. At the regional scale, however, the choice of the industrial and fossil fuel inventory can make a difference. The estimated baseline emission fluxes for SO2, BC and POM are within the estimated uncertainties of the four experiments. The resulting emissions were compared against projected emissions for the year 2010 for SO2, BC and POM. The new estimate present larger emissions than the projections for all three species, with larger differences for SO2 than POM and BC. These projected emissions are in general outside the uncertainties of the estimated emission inventories.

scholarly journals Variability of springtime transpacific pollution transport during 2000–2006: the INTEX-B mission in the context of previous years

2010 ◽  
Vol 10 (3) ◽  
pp. 1345-1359 ◽  
Author(s):  
G. G. Pfister ◽  
L. K. Emmons ◽  
D. P. Edwards ◽  
A. Arellano ◽  
T. Campos ◽  
...  
Keyword(s):  
Transport Model ◽  
Pollution Transport ◽  
Chemistry Transport Model ◽  
Pollution Levels ◽  
Annual Variability ◽  
Source Regions ◽  
Time Period ◽  
The Pacific ◽  
The Us ◽  
Transport Experiment

Abstract. We analyze the transport of pollution across the Pacific during the NASA INTEX-B (Intercontinental Chemical Transport Experiment Part B) campaign in spring 2006 and examine how this year compares to the time period for 2000 through 2006. In addition to aircraft measurements of carbon monoxide (CO) collected during INTEX-B, we include in this study multi-year satellite retrievals of CO from the Measurements of Pollution in the Troposphere (MOPITT) instrument and simulations from the chemistry transport model MOZART-4. Model tracers are used to examine the contributions of different source regions and source types to pollution levels over the Pacific. Additional modeling studies are performed to separate the impacts of inter-annual variability in meteorology and dynamics from changes in source strength. Interannual variability in the tropospheric CO burden over the Pacific and the US as estimated from the MOPITT data range up to 7% and a somewhat smaller estimate (5%) is derived from the model. When keeping the emissions in the model constant between years, the year-to-year changes are reduced (2%), but show that in addition to changes in emissions, variable meteorological conditions also impact transpacific pollution transport. We estimate that about 1/3 of the variability in the tropospheric CO loading over the contiguous US is explained by changes in emissions and about 2/3 by changes in meteorology and transport. Biomass burning sources are found to be a larger driver for inter-annual variability in the CO loading compared to fossil and biofuel sources or photochemical CO production even though their absolute contributions are smaller. Source contribution analysis shows that the aircraft sampling during INTEX-B was fairly representative of the larger scale region, but with a slight bias towards higher influence from Asian contributions.

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