Morphological features and mixing states of soot-containing particles in the marine boundary layer over the Indian and Southern Oceans

Ueda, Sayako; Osada, Kazuo; Hara, Keiichiro; Yabuki, Masanori; Hashihama, Fuminori; Kanda, Jun

doi:10.5194/acp-2017-1179

Cited by 8 publications

(8 citation statements)

References 36 publications

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“…EBC is expected to be transported from mid-latitudes and low latitudes, as suggested by Fiebig et al (2009) and Hara et al (2010). Therefore, EBC mixing states might be changed by aging processes near source regions and during long-range transport (Shiraiwa et al, 2007;Saleh et al, 2013Saleh et al, , 2014Ueda et al, 2018 (Wagenbach, 1996;Weller et al, 2013).…”

Section: Chaser (Miroc-esm) Modelmentioning

confidence: 99%

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Seasonal features and origins of carbonaceous aerosols at Syowa Station, Antarctica

Hara¹,

Sudo²,

Ohnishi³

et al. 2019

Preprint

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Abstract. We measured equivalent black carbon (EBC) concentrations at Syowa Station, Antarctica from February 2005 to characterize seasonal features of EBC concentrations and their origins, and to monitor long-range transport of aerosols from mid-latitudes to the Antarctic coast. Results show that EBC concentrations were below the detection limit (0.2&#8201;ng&#8201;m&#8722;3) to 63.8&#8201;ng&#8201;m&#8722;3 at Syowa Station (median, 1.8&#8201;ng&#8201;m&#8722;3; mean, 2.7&#8201;ng&#8201;m&#8722;3 during the measurement period). Although seasonal features and year-to-year variations of EBC concentrations were observed, no long-term trend of EBC concentrations was clear during our measurement period. Seasonal features of EBC concentrations showed a spring maximum during September&#8211;October at Syowa Station. The absorption &#197;ngstr&#246;m exponent (AAE) was 0.5&#8211;1.0 during April&#8211;October; it reached its maximum values (1.0&#8211;1.5) during summer. The AAE features imply that EBC was mixed internally in the Antarctic troposphere and that organic aerosols engendered high AAE in the summer. To elucidate EBC transport processes, origins, and the potential source area (PSA), we compared EBC data to backward trajectory analysis and model simulation. Results show that EBC might be transported directly to Syowa Station from mid-latitudes mainly via the boundary layer and the lower free troposphere. Some BC was transported to Antarctic regions via the upper free troposphere. Biomass burning in South America and southern Africa is the most dominant PSA for BC transported to Syowa Station. Fossil fuel combustion in South America and southern Africa also have important contributions.

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Section: Chaser (Miroc-esm) Modelmentioning

confidence: 99%

“…). Indeed,Ueda et al (2018) showed that EBC was present mostly as internal mixtures in the marine boundary layer (MBL) of the Southern Ocean. Therefore, lower AAE in April-October suggests that EBC was dominantly present as the coated EBC particles (internal mixtures) at Syowa.…”

mentioning

confidence: 99%

Seasonal features and origins of carbonaceous aerosols at Syowa Station, Antarctica

Hara¹,

Sudo²,

Ohnishi³

et al. 2019

Preprint

Self Cite

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show abstract

“…Chemical analysis of the mixing state of atmospheric aerosol particles has been conducted primarily by offline electron microscopy (Adachi et al, 2014, 2016; Moffet et al, 2016; Ueda et al, 2018). Transmission electron microscopy (TEM) combined with elemental composition analysis can provide a direct view of the mixing state of particles.…”

Section: Introductionmentioning

confidence: 99%

Mixing State of Black Carbon Particles in Asian Outflow Observed at a Remote Site in Taiwan in the Spring of 2017

Sun

Adachi²,

Misawa

et al. 2020

JGR Atmospheres

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Anthropogenic emissions of aerosols and trace gases from East Asia have significant impacts on air quality and climate on regional and global scales. We conducted intensive measurements of aerosols at a remote site (Cape Fuguei; 25.30°N, 121.54°E) in Taiwan in the spring of 2017, focusing on the chemical composition and mixing state of aerosols in Asian outflow. A laser‐induced incandescence–mass spectrometric analyzer (LII‐MS) was used to measure the chemical composition of aerosols internally or externally mixed with black carbon (BC). Offline analysis by transmission electron microscopy (TEM) was used to characterize the mixing state of aerosols. The observation period was classified into long‐range transport (LRT) periods and local pollution periods on the basis of cluster analysis of 3‐day backward trajectories. LII‐MS data showed that the average mass fractions of sulfate and nitrate internally mixed with BC were 7% ± 13% and 11% ± 15%, respectively, for high‐pollution episodes during LRT periods. By TEM analysis of selected samples from LRT periods, the number fraction of aerosol particles internally mixed with BC was estimated to be 5%–36% for core–shell types and 5%–23% for attached types. Factors affecting the differences between LII‐MS and TEM measurements are discussed. TEM data indicated the presence of a variety of aerosol mixing states in widespread regional pollution transported 500–1,000 km downwind of emission sources. Our results provide new constraints for three‐dimensional models that might resolve the mixing state of aerosol particles, which are critical for accurately estimating the radiative impact of BC.

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“…Moreover, previous studies found that large amounts of light-absorbing aerosols (e.g., black carbon and brown carbon) from continental polluted air can be transported into the open ocean air and significantly influence the radiative balance of the marine boundary layer (Kang et al, 2018;Kondo et al, 2016;Ueda et al, 2018;Zhang et al, 2014). Therefore, it is significant to understand the physicochemical properties of continental anthropogenic aerosol particles in marine air.…”

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confidence: 99%

Long-range transport of anthropogenic air pollutants into the marine air: Insight into fine particle transport and chloride depletion on sea salts

Liu

Gao

et al. 2021

Preprint

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Abstract. Long-range transport of anthropogenic air pollutants from East Asia can affect the downwind marine air quality during spring and winter. Long-range transport of continental air pollutants and their interaction with sea salt aerosols (SSA) significantly modify the radiative forcing of marine aerosols and influence ocean biogeochemical cycling. Previous studies poorly characterize variations of aerosol particles along with air mass transport from the continental edge to the remote ocean. Here, the research ship R/V Dongfanghong 2 traveled from the eastern China seas (ECS) to the northwestern Pacific Ocean (NWPO) to understand what and how air pollutants were transported from the highly polluted continental air to clean marine air in spring. A transmission electron microscope (TEM) was used to find the long-range transported anthropogenic particles and the possible Cl-depletion phenomenon of SSA in marine air. Primary and secondary anthropogenic aerosols were identified and dramatically declined from 87 % to 8 % by number from the ECS to remote NWPO. For the SSA aging, 86 % of SSA particles in the ECS were identified as fully aged, while the proportion of fully aged SSA particles in the NWPO decreased to 31 %. The result highlights that anthropogenic acidic gases in the troposphere (e.g., SO2, NOx, and volatile organic compounds) were transported longer distances compared to the anthropogenic aerosol and could exert a significant impact on marine aerosols in the NWPO. These results show that anthropogenic particles and gases from East Asia significantly perturb aerosol chemistry in marine air. The optical properties and cloud condensation nucleation of the modified SSA particles should be incorporated into the more accurately modeling of clouds in the ECS and NWPO in spring and winter.

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Morphological features and mixing states of soot-containing particles in the marine boundary layer over the Indian and Southern Oceans

Cited by 8 publications

References 36 publications

Seasonal features and origins of carbonaceous aerosols at Syowa Station, Antarctica

Seasonal features and origins of carbonaceous aerosols at Syowa Station, Antarctica

Mixing State of Black Carbon Particles in Asian Outflow Observed at a Remote Site in Taiwan in the Spring of 2017

Long-range transport of anthropogenic air pollutants into the marine air: Insight into fine particle transport and chloride depletion on sea salts

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