Aerosol size distribution seasonal characteristics measured in Tiksi, Russian Arctic
Four years of continuous aerosol number size distribution measurements from the Arctic Climate Observatory in Tiksi, Russia, are analyzed. Tiksi is located in a region where in situ information on aerosol particle properties has not been previously available. Particle size distributions were mea...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-02-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/16/1271/2016/acp-16-1271-2016.pdf |
| Summary: | Four years of continuous aerosol number size distribution
measurements from the Arctic Climate Observatory in Tiksi, Russia, are analyzed.
Tiksi is located in a region where in situ information on aerosol particle
properties has not been previously available. Particle size distributions
were measured with a differential mobility particle sizer (in the diameter
range of 7–500 nm) and with an aerodynamic particle sizer (in the diameter range of 0.5–10 μm). Source region effects on particle modal features and number, and
mass concentrations are presented for different seasons. The monthly median
total aerosol number concentration in Tiksi ranges from 184 cm<sup>−3</sup> in
November to 724 cm<sup>−3</sup> in July, with a local maximum in March of 481 cm<sup>−3</sup>. The total mass concentration has a distinct maximum in
February–March of 1.72–2.38 μg m<sup>−3</sup> and two minimums in June (0.42 μg m<sup>−3</sup>) and in September–October (0.36–0.57 μg m<sup>−3</sup>).
These seasonal cycles in number and mass concentrations are related to
isolated processes and phenomena such as Arctic haze in early spring, which
increases accumulation and coarse-mode numbers, and secondary particle
formation in spring and summer, which affects the nucleation and Aitken mode
particle concentrations. Secondary particle formation was frequently observed
in Tiksi and was shown to be slightly more common in marine, in comparison to
continental, air flows. Particle formation rates were the highest in spring, while the particle growth rates peaked in summer. These results suggest
two different origins for secondary particles, anthropogenic pollution being
the important source in spring and biogenic emissions being significant in summer. The impact
of temperature-dependent natural emissions on aerosol and cloud condensation
nuclei numbers was significant: the increase in both the particle mass and the
CCN (cloud condensation nuclei) number with temperature was found to be higher than in any previous study
done over the boreal forest region. In addition to the precursor emissions
of biogenic volatile organic compounds, the frequent Siberian forest fires,
although far away, are suggested to play a role in Arctic aerosol composition
during the warmest months. Five fire events were isolated based on clustering
analysis, and the particle mass and cloud condensation nuclei number were shown to
be somewhat affected by these events. In addition, during calm and cold
months, aerosol concentrations were occasionally increased by local aerosol
sources in trapping inversions. These results provide valuable information on
interannual cycles and sources of Arctic aerosols. |
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| ISSN: | 1680-7316 1680-7324 |