scholarly journals Aerosols at the Poles: An AeroCom Phase II multi-model evaluation

2017 ◽  
Author(s):  
Maria Sand ◽  
Bjørn H. Samset ◽  
Yves Balkanski ◽  
Susanne Bauer ◽  
Nicolas Bellouin ◽  
...  
Keyword(s):  
Phase Ii ◽  
Biomass Burning ◽  
Radiative Forcing ◽  
Fossil Fuel ◽  
Organic Aerosols ◽  
Global Climate Models ◽  
Sea Salt ◽  
The Arctic ◽  
Anthropogenic Aerosols ◽  
The Antarctic

Abstract. Atmospheric aerosols from anthropogenic and natural sources reach the Polar Regions through long-range transport. Such transport is however poorly constrained in present day global climate models, and few multi-model evaluations of Polar anthropogenic aerosol radiative forcing exist. Here we compare the aerosol optical depth (AOD) at 550 nm from simulations with 16 global aerosol models from the AeroCom phase II model inter-comparison project with available observations at both Poles. We show that the annual mean multi-model median is representative of the observations in Arctic, but that the inter-model spread is large. We also document the geographical distribution and seasonal cycle of the AOD for the individual aerosol species; black carbon (BC) from fossil fuel and biomass burning, sulfate, organic aerosols (OA), dust and sea-salt. For a subset of models that represent nitrate and secondary organic aerosols (SOA), we document the role of these aerosols at high latitudes. The seasonal dependence of natural and anthropogenic aerosols differs with natural aerosols peaking in the winter (sea-salt) and spring (dust), whereas AOD from anthropogenic aerosols peaks during late spring/summer. The models produce a median annual mean (AOD) of 0.07 in the Arctic (defined here as north of 60° N). The models also predict a noteworthy aerosol transport to the Antarctic (south of 70° S) with a resulting AOD varying between 0.01–0.02. The models have also estimated the shortwave anthropogenic radiative forcing contributions to the direct aerosol effect (DAE) associated with BC and OA from fossil fuel and biofuel (FF), sulfate, SOA, nitrate, and biomass burning from BC and OA emissions combined. The Arctic modeled annual mean DAE is slightly negative (−0.12 W m−2), dominated by a positive BC FF DAE during spring and a negative sulfate DAE during summer. The Antarctic DAE is governed by BC FF. We perform sensitivity experiments with one of the AeroCom models (GISS modelE) to investigate how regional emissions of BC and sulfate and the lifetime of BC influence the Arctic and Antarctic AOD. A doubling of emissions in East Asia, result in a 33 % increase in Arctic AOD of BC. However, radical changes such as reducing the e-folding lifetime by half or doubling it, still fall within the AeroCom model range.

scholarly journals Aerosols at the poles: an AeroCom Phase II multi-model evaluation

2017 ◽  
Vol 17 (19) ◽  
pp. 12197-12218 ◽  
Author(s):  
Maria Sand ◽  
Bjørn H. Samset ◽  
Yves Balkanski ◽  
Susanne Bauer ◽  
Nicolas Bellouin ◽  
...  
Keyword(s):  
Phase Ii ◽  
Biomass Burning ◽  
Radiative Forcing ◽  
Fossil Fuel ◽  
Organic Aerosols ◽  
Sea Salt ◽  
The Arctic ◽  
Radiation Balance ◽  
Anthropogenic Aerosols ◽  
The Antarctic

Abstract. Atmospheric aerosols from anthropogenic and natural sources reach the polar regions through long-range transport and affect the local radiation balance. Such transport is, however, poorly constrained in present-day global climate models, and few multi-model evaluations of polar anthropogenic aerosol radiative forcing exist. Here we compare the aerosol optical depth (AOD) at 550 nm from simulations with 16 global aerosol models from the AeroCom Phase II model intercomparison project with available observations at both poles. We show that the annual mean multi-model median is representative of the observations in Arctic, but that the intermodel spread is large. We also document the geographical distribution and seasonal cycle of the AOD for the individual aerosol species: black carbon (BC) from fossil fuel and biomass burning, sulfate, organic aerosols (OAs), dust, and sea-salt. For a subset of models that represent nitrate and secondary organic aerosols (SOAs), we document the role of these aerosols at high latitudes.The seasonal dependence of natural and anthropogenic aerosols differs with natural aerosols peaking in winter (sea-salt) and spring (dust), whereas AOD from anthropogenic aerosols peaks in late spring and summer. The models produce a median annual mean AOD of 0.07 in the Arctic (defined here as north of 60° N). The models also predict a noteworthy aerosol transport to the Antarctic (south of 70° S) with a resulting AOD varying between 0.01 and 0.02. The models have estimated the shortwave anthropogenic radiative forcing contributions to the direct aerosol effect (DAE) associated with BC and OA from fossil fuel and biofuel (FF), sulfate, SOAs, nitrate, and biomass burning from BC and OA emissions combined. The Arctic modelled annual mean DAE is slightly negative (−0.12 W m−2), dominated by a positive BC FF DAE in spring and a negative sulfate DAE in summer. The Antarctic DAE is governed by BC FF. We perform sensitivity experiments with one of the AeroCom models (GISS modelE) to investigate how regional emissions of BC and sulfate and the lifetime of BC influence the Arctic and Antarctic AOD. A doubling of emissions in eastern Asia results in a 33 % increase in Arctic AOD of BC. A doubling of the BC lifetime results in a 39 % increase in Arctic AOD of BC. However, these radical changes still fall within the AeroCom model range.

scholarly journals Radiative forcing of the direct aerosol effect from AeroCom Phase II simulations

2012 ◽  
Vol 12 (8) ◽  
pp. 22355-22413 ◽  
Author(s):  
G. Myhre ◽  
B. H. Samset ◽  
M. Schulz ◽  
Y. Balkanski ◽  
S. Bauer ◽  
...  
Keyword(s):  
Phase Ii ◽  
Radiative Forcing ◽  
Fossil Fuel ◽  
Organic Aerosols ◽  
Anthropogenic Aerosols ◽  
Aerosol Effect ◽  
Time Period ◽  
Aerosol Distribution ◽  
The Mean ◽  
The Individual

Abstract. We report on the AeroCom Phase II direct aerosol effect (DAE) experiment where 15 detailed global aerosol models have been used to simulate the changes in the aerosol distribution over the industrial era. All 15 models have estimated the radiative forcing (RF) of the anthropogenic DAE, and have taken into account anthropogenic sulphate, black carbon (BC) and organic aerosols (OA) from fossil fuel, biofuel, and biomass burning emissions. In addition several models have simulated the DAE of anthropogenic nitrate and anthropogenic influenced secondary organic aerosols (SOA). The model simulated all-sky RF of the DAE from total anthropogenic aerosols has a range from −0.58 to −0.02 W m−2, with a mean of −0.30 W m−2 for the 15 models. Several models did not include nitrate or SOA and modifying the estimate by accounting for this with information from the other AeroCom models reduces the range and slightly strengthens the mean. Modifying the model estimates for missing aerosol components and for the time period 1750 to 2010 results in a mean RF for the DAE of −0.39 W m−2. Compared to AeroCom Phase I (Schulz et al., 2006) we find very similar spreads in both total DAE and aerosol component RF. However, the RF of the total DAE is stronger negative and RF from BC from fossil fuel and biofuel emissions are stronger positive in the present study than in the previous AeroCom study. We find a tendency for models having a strong (positive) BC RF to also have strong (negative) sulphate or OA RF. This relationship leads to smaller uncertainty in the total RF of the DAE compared to the RF of the sum of the individual aerosol components. The spread in results for the individual aerosol components is substantial, and can be divided into diversities in burden, mass extinction coefficient (MEC), and normalized RF with respect to AOD. We find that these three factors give similar contributions to the spread in results.

scholarly journals Radiative forcing of the direct aerosol effect from AeroCom Phase II simulations

2013 ◽  
Vol 13 (4) ◽  
pp. 1853-1877 ◽  
Author(s):  
G. Myhre ◽  
B. H. Samset ◽  
M. Schulz ◽  
Y. Balkanski ◽  
S. Bauer ◽  
...  
Keyword(s):  
Phase Ii ◽  
Radiative Forcing ◽  
Fossil Fuel ◽  
Organic Aerosols ◽  
Anthropogenic Aerosols ◽  
Aerosol Effect ◽  
Time Period ◽  
Aerosol Distribution ◽  
The Mean ◽  
The Individual

Abstract. We report on the AeroCom Phase II direct aerosol effect (DAE) experiment where 16 detailed global aerosol models have been used to simulate the changes in the aerosol distribution over the industrial era. All 16 models have estimated the radiative forcing (RF) of the anthropogenic DAE, and have taken into account anthropogenic sulphate, black carbon (BC) and organic aerosols (OA) from fossil fuel, biofuel, and biomass burning emissions. In addition several models have simulated the DAE of anthropogenic nitrate and anthropogenic influenced secondary organic aerosols (SOA). The model simulated all-sky RF of the DAE from total anthropogenic aerosols has a range from −0.58 to −0.02 Wm−2, with a mean of −0.27 Wm−2 for the 16 models. Several models did not include nitrate or SOA and modifying the estimate by accounting for this with information from the other AeroCom models reduces the range and slightly strengthens the mean. Modifying the model estimates for missing aerosol components and for the time period 1750 to 2010 results in a mean RF for the DAE of −0.35 Wm−2. Compared to AeroCom Phase I (Schulz et al., 2006) we find very similar spreads in both total DAE and aerosol component RF. However, the RF of the total DAE is stronger negative and RF from BC from fossil fuel and biofuel emissions are stronger positive in the present study than in the previous AeroCom study. We find a tendency for models having a strong (positive) BC RF to also have strong (negative) sulphate or OA RF. This relationship leads to smaller uncertainty in the total RF of the DAE compared to the RF of the sum of the individual aerosol components. The spread in results for the individual aerosol components is substantial, and can be divided into diversities in burden, mass extinction coefficient (MEC), and normalized RF with respect to AOD. We find that these three factors give similar contributions to the spread in results.

scholarly journals Possible influence of anthropogenic aerosols on cirrus clouds and anthropogenic forcing

2009 ◽  
Vol 9 (3) ◽  
pp. 879-896 ◽  
Author(s):  
J. E. Penner ◽  
Y. Chen ◽  
M. Wang ◽  
X. Liu
Keyword(s):  
Biomass Burning ◽  
Radiative Forcing ◽  
Fossil Fuel ◽  
Ice Nucleation ◽  
Cirrus Clouds ◽  
Solid Particles ◽  
Sulfate Aerosols ◽  
Anthropogenic Aerosols ◽  
Upper Troposphere ◽  
Aerosol Model

Abstract. Cirrus clouds have a net warming effect on the atmosphere and cover about 30% of the Earth's area. Aerosol particles initiate ice formation in the upper troposphere through modes of action that include homogeneous freezing of solution droplets, heterogeneous nucleation on solid particles immersed in a solution, and deposition nucleation of vapor onto solid particles. Here, we examine the possible change in ice number concentration from anthropogenic soot originating from surface sources of fossil fuel and biomass burning, from anthropogenic sulfate aerosols, and from aircraft that deposit their aerosols directly in the upper troposphere. We use a version of the aerosol model that predicts sulfate number and mass concentrations in 3-modes and includes the formation of sulfate aerosol through homogeneous binary nucleation as well as a version that only predicts sulfate mass. The 3-mode version best represents the Aitken aerosol nuclei number concentrations in the upper troposphere which dominated ice crystal residues in the upper troposphere. Fossil fuel and biomass burning soot aerosols with this version exert a radiative forcing of −0.3 to −0.4 Wm−2 while anthropogenic sulfate aerosols and aircraft aerosols exert a forcing of −0.01 to 0.04 Wm−2 and −0.16 to −0.12 Wm−2, respectively, where the range represents the forcing from two parameterizations for ice nucleation. The sign of the forcing in the mass-only version of the model depends on which ice nucleation parameterization is used and can be either positive or negative. The magnitude of the forcing in cirrus clouds can be comparable to the forcing exerted by anthropogenic aerosols on warm clouds, but this forcing has not been included in past assessments of the total anthropogenic radiative forcing of climate.

scholarly journals Possible influence of anthropogenic aerosols on cirrus clouds and anthropogenic forcing

2008 ◽  
Vol 8 (4) ◽  
pp. 13903-13942 ◽  
Author(s):  
J. E. Penner ◽  
Y. Chen ◽  
M. Wang ◽  
X. Liu
Keyword(s):  
Biomass Burning ◽  
Radiative Forcing ◽  
Fossil Fuel ◽  
Cirrus Clouds ◽  
Solid Particles ◽  
Sulfate Aerosols ◽  
Anthropogenic Aerosols ◽  
Upper Troposphere ◽  
Model Configuration ◽  
Homogeneous Freezing

Abstract. Cirrus clouds have a net warming effect on the atmosphere and cover about 30% of the Earth's area. Aerosol particles initiate ice formation in the upper troposphere through modes of action that include homogeneous freezing of solution droplets, heterogeneous nucleation on solid particles immersed in a solution, and deposition nucleation of vapor onto solid particles. Here, we examine the possible change in ice number concentration from anthropogenic soot originating from surface sources of fossil fuel and biomass burning, from anthropogenic sulfate aerosols, and from aircraft that deposit their aerosols directly in the upper troposphere. We find that fossil fuel and biomass burning soot aerosols exert a radiative forcing of −0.68 to 0.01 Wm−2 while anthropogenic sulfate aerosols exert a forcing of −0.01 to 0.18 Wm−2. Our calculations show that the sign of the forcing by aircraft soot depends on the model configuration and can be both positive or negative, ranging from −0.16 to 0.02 Wm−2. The magnitude of the forcing in cirrus clouds can be comparable to the forcing exerted by anthropogenic aerosols on warm clouds, but this forcing has not been included in past assessments of the total anthropogenic radiative forcing of climate.

scholarly journals Fossil fuel combustion and biomass burning sources of global black carbon from GEOS-Chem simulation and carbon isotope measurements

2019 ◽  
Vol 19 (17) ◽  
pp. 11545-11557 ◽  
Author(s):  
Ling Qi ◽  
Shuxiao Wang
Keyword(s):  
Black Carbon ◽  
Carbon Isotope ◽  
Biomass Burning ◽  
Fossil Fuel ◽  
Transport Model ◽  
Fuel Combustion ◽  
The Arctic ◽  
Fossil Fuel Combustion ◽  
The Antarctic ◽  
Isotope Measurements

Abstract. We identify sources (fossil fuel combustion versus biomass burning) of black carbon (BC) in the atmosphere and in deposition using a global 3-D chemical transport model GEOS-Chem. We validate the simulated sources against carbon isotope measurements of BC around the globe and find that the model reproduces mean biomass burning contribution (fbb; %) in various regions within a factor of 2 (except in Europe, where fbb is underestimated by 63 %). GEOS-Chem shows that contribution from biomass burning in the Northern Hemisphere (fbb: 35±14 %) is much less than that in the Southern Hemisphere (50±11 %). The largest atmospheric fbb is in Africa (64±20 %). Comparable contributions from biomass burning and fossil fuel combustion are found in southern (S) Asia (53±10 %), southeastern (SE) Asia (53±11 %), S America (47±14 %), the S Pacific (47±7 %), Australia (53±14 %) and the Antarctic (51±2 %). fbb is relatively small in eastern Asia (40±13 %), Siberia (35±8 %), the Arctic (33±6 %), Canada (31±7 %), the US (25±4 %) and Europe (19±7 %). Both observations and model results suggest that atmospheric fbb is higher in summer (59 %–78 %, varying with sub-regions) than in winter (28 %–32 %) in the Arctic, while it is higher in winter (42 %–58 %) and lower in summer (16 %–42 %) over the Himalayan–Tibetan Plateau. The seasonal variations of Atmosphericfbb are relatively flat in North America, Europe and Asia. We conducted four experiments to investigate the uncertainties associated with biofuel emissions, hygroscopicity of BC in fresh emissions, the aging rate and size-resolved wet scavenging. We find that doubling biofuel emissions for domestic heating north of 45∘ N increases fbb values in Europe in winter by ∼30 %, reducing the discrepancy between observed and modeled atmospheric fbb from −63 % to −54 %. The remaining large negative discrepancy between model and observations suggests that the biofuel emissions are probably still underestimated at high latitudes. Increasing the fraction of thickly coated hydrophilic BC from 20 % to 70 % in fresh biomass burning plumes increases the fraction of hydrophilic BC in biomass burning plumes by 0 %–20 % (varying with seasons and regions) and thereby reduces atmospheric fbb by up to 11 %. Faster aging (4 h e-folding time versus 1.15 d e-folding time) of BC in biomass burning plumes reduces atmospheric fbb by 7 % (1 %–14 %, varying with seasons and regions), with the largest reduction in remote regions, such as the Arctic, the Antarctic and the S Pacific. Using size-resolved scavenging accelerates scavenging of BC particles in both fossil fuel and biomass burning plumes, with a faster scavenging of BC in fossil fuel plumes. Thus, atmospheric fbb increases in most regions by 1 %–14 %. Overall, atmospheric fbb is determined mainly by fbb in emissions and, to a lesser extent, by atmospheric processes, such as aging and scavenging. This confirms the assumption that fbb in local emissions determines atmospheric fbb in previous studies, which compared measured atmospheric fbb directly with local fbb in bottom-up emission inventories.

scholarly journals Fossil fuel combustion and biomass burning sources of global black carbon

2019 ◽  
Author(s):  
Ling Qi ◽  
Shuxiao Wang
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Fossil Fuel ◽  
Transport Model ◽  
The Arctic ◽  
Fossil Fuel Combustion ◽  
Chemical Transport Model ◽  
Fresh Biomass ◽  
The Us ◽  
The Antarctic

Abstract. We identify sources (fossil fuel versus biomass burning) of black carbon (BC) in the atmosphere and in deposition using a global 3D chemical transport model GEOS-Chem. We validate the simulated sources against carbon isotope measurements of BC around the globe and find that the model reproduces biomass burning contribution (fbb, %) in various regions within a factor of 2. GEOS-Chem shows that contribution from biomass burning in the Northern Hemisphere (fbb: 34 %) is much less than that in the Southern Hemisphere (52 %). Specifically, we find comparable contribution from biomass burning and fossil fuel in South Asia, S. America, S. Pacific, Australia and the Antarctic. fbb is the largest in Africa (64 %), followed by that in East Asia (40 %), Siberia (35 %), the Arctic (33 %), Canada (31 %), the US (25 %), and Europe (19 %). fbb is higher in summer (59–78 %) than in winter (28–32 %) in the Arctic, while it is higher in winter (42–58 %) and lower in summer (16–42 %) over the Himalayan–Tibetan plateau. The seasonal variations of fbb are relatively flat in North America, Europe, and Asia. We find that double biofuel emissions for domestic heating during cold seasons northern than 45° N increases fbb values in the Arctic and Europe in winter by ~ 30 %, resulting in a ~ 20 % reduction of discrepancies of fbb in the two regions. The remaining large negative discrepancies (Europe: 41 %; Arctic: 46 %) suggest that the biofuel emissions are probably still underestimated at high latitudes. Increasing fraction of thickly coated hydrophilic BC from 20 % to 70 % in fresh biomass burning plumes increases the fraction of hydrophilic BC in biomass burning plumes by 0–20 % (vary with seasons and regions), and thereby reduces atmospheric fbb by up to 11 %. Faster aging (4 hour e-folding time versus 1.15 days of e-folding time) of BC in biomass burning plumes reduces atmospheric fbb by 7 % (1–14 %), with the largest reduction in remote regions, such as the Arctic, the Antarctic and S. Pacific. Using size resolved scavenging accelerates scavenging of BC particles in both fossil fuel and biomass burning plumes, with a larger increase of the former. Thus, atmospheric fbb increases in most regions by 1–14 %. Overall, atmospheric fbb is determined by fbb in emissions mainly and by atmospheric processes, such as aging and scavenging, to a less extent.

scholarly journals Modeled Arctic sea ice evolution through 2300 in CMIP5 extended RCPs

2014 ◽  
Vol 8 (1) ◽  
pp. 1383-1406 ◽  
Author(s):  
P. J. Hezel ◽  
T. Fichefet ◽  
F. Massonnet
Keyword(s):  
Sea Ice ◽  
Radiative Forcing ◽  
Climate Models ◽  
Global Climate ◽  
Arctic Sea Ice ◽  
Global Climate Models ◽  
The Arctic ◽  
Sea Ice Extent ◽  
Arctic Sea ◽  
Arctic Sea Ice Extent

Abstract. Almost all global climate models and Earth system models that participated in the Coupled Model Intercomparison Project 5 (CMIP5) show strong declines in Arctic sea ice extent and volume under the highest forcing scenario of the Radiative Concentration Pathways (RCPs) through 2100, including a transition from perennial to seasonal ice cover. Extended RCP simulations through 2300 were completed for a~subset of models, and here we examine the time evolution of Arctic sea ice in these simulations. In RCP2.6, the summer Arctic sea ice extent increases compared to its minimum following the peak radiative forcing in 2044 in all 9 models. RCP4.5 demonstrates continued summer Arctic sea ice decline due to continued warming on longer time scales. These two scenarios imply that summer sea ice extent could begin to recover if and when radiative forcing from greenhouse gas concentrations were to decrease. In RCP8.5 the Arctic Ocean reaches annually ice-free conditions in 7 of 9 models. The ensemble of simulations completed under the extended RCPs provide insight into the global temperature increase at which sea ice disappears in the Arctic and reversibility of declines in seasonal sea ice extent.

scholarly journals Microphysics of summer clouds in central West Antarctica simulated by the Polar Weather Research and Forecasting Model (WRF) and the Antarctic Mesoscale Prediction System (AMPS)

2019 ◽  
Vol 19 (19) ◽  
pp. 12431-12454 ◽  
Author(s):  
Keith M. Hines ◽  
David H. Bromwich ◽  
Sheng-Hung Wang ◽  
Israel Silber ◽  
Johannes Verlinde ◽  
...  
Keyword(s):  
Liquid Water ◽  
Radiative Forcing ◽  
Weather Prediction ◽  
The Arctic ◽  
Weather Research And Forecasting ◽  
Forecasting Model ◽  
Prediction System ◽  
West Antarctic ◽  
The Antarctic ◽  
Weather Research

Abstract. The Atmospheric Radiation Measurement (ARM) West Antarctic Radiation Experiment (AWARE) provided a highly detailed set of remote-sensing and surface observations to study Antarctic clouds and surface energy balance, which have received much less attention than for the Arctic due to greater logistical challenges. Limited prior Antarctic cloud observations have slowed the progress of numerical weather prediction in this region. The AWARE observations from the West Antarctic Ice Sheet (WAIS) Divide during December 2015 and January 2016 are used to evaluate the operational forecasts of the Antarctic Mesoscale Prediction System (AMPS) and new simulations with the Polar Weather Research and Forecasting Model (WRF) 3.9.1. The Polar WRF 3.9.1 simulations are conducted with the WRF single-moment 5-class microphysics (WSM5C) used by the AMPS and with newer generation microphysics schemes. The AMPS simulates few liquid clouds during summer at the WAIS Divide, which is inconsistent with observations of frequent low-level liquid clouds. Polar WRF 3.9.1 simulations show that this result is a consequence of WSM5C. More advanced microphysics schemes simulate more cloud liquid water and produce stronger cloud radiative forcing, resulting in downward longwave and shortwave radiation at the surface more in agreement with observations. Similarly, increased cloud fraction is simulated with the more advanced microphysics schemes. All of the simulations, however, produce smaller net cloud fractions than observed. Ice water paths vary less between the simulations than liquid water paths. The colder and drier atmosphere driven by the Global Forecast System (GFS) initial and boundary conditions for AMPS forecasts produces lesser cloud amounts than the Polar WRF 3.9.1 simulations driven by ERA-Interim.

scholarly journals Sources and mixing state of summertime background aerosol in the northwestern Mediterranean basin

2017 ◽  
Author(s):  
Jovanna Arndt ◽  
Jean Sciare ◽  
Marc Mallet ◽  
Greg C. Roberts ◽  
Nicolas Marchand ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Biomass Burning ◽  
Mediterranean Basin ◽  
Particle Number ◽  
Fossil Fuel ◽  
Western Mediterranean ◽  
Sea Salt ◽  
Quantitative Measurements ◽  
Combustion Particles ◽  
Mass Concentrations

Abstract. An aerosol time-of-flight mass spectrometer (ATOFMS) was employed to provide real-time single particle mixing state and thereby source information for aerosols impacting the western Mediterranean basin during the ChArMEx-ADRIMED and SAF-MED campaigns in summer 2013. The ATOFMS measurements were made at a ground-based remote site on the northern tip of Corsica Island. 27 distinct ATOFMS particle classes were identified and subsequently grouped into 8 general categories: EC-rich (elemental carbon), K-rich, Na-rich, Amines, OC-rich (organic carbon), V-rich, Fe-rich and Ca-rich. Mass concentrations were reconstructed for the ATOFMS particle classes and found to be in good agreement with other co-located quantitative measurements (PM1, black carbon (BC), organic carbon, sulfate mass and ammonium mass). Total ATOFMS reconstructed mass (PM2.5) accounted for 70–90 % of measured PM10 mass and was comprised of regionally transported fossil fuel (EC-rich) and biomass burning (K-rich) particles. The accumulation of these transported particles was favoured by repeated and extended periods of air mass stagnation over the western Mediterranean during the sampling campaigns. The single particle mass spectra proved to be valuable source markers, allowing the identification of fossil fuel and biomass burning combustion sources, and therefore highly complementary to quantitative measurements made by particle-into-liquid sampler ion chromatography (PILS-IC) and an aerosol chemical speciation monitor (ACSM), which have demonstrated that PM1 and PM10 were comprised predominantly of sulfate, ammonium and OC. Good temporal agreement was observed between ATOFMS EC-rich and K-rich particle mass concentrations and combined mass concentrations of BC, sulfate, ammonium and low volatility oxygenated organic aerosol (LV-OOA). This combined information suggests that combustion of fossil fuels and biomass produced primary EC- and OC-containing particles, which then accumulated ammonium, sulfate and alkylamines during regional transport. Three other sources were also identified: local biomass burning, marine and shipping. Local combustion particles (emitted in Corsica) contributed little to PM2.5 particle number and mass concentrations but were easily distinguished from regional combustion particles. Marine emissions comprised fresh and aged sea salt; the former detected mostly during one 5-day event during which it accounted for 50–80 % of sea salt aerosol mass, while the latter detected throughout the sampling period. Dust was not efficiently detected by the ATOFMS, and support measurements showed that it was mainly in the PM2.5–10 fraction. Shipping particles, identified using markers for heavy fuel oil combustion, were associated with regional emissions, and represented only a small fraction of PM2.5 particle number and mass concentration at the site.

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