Aerosol size distribution seasonal characteristics measured in Tiksi, Russian Arctic

Abstract

Abstract. 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−3 in November to 724 cm−3 in July, with a local maximum in March of 481 cm−3. The total mass concentration has a distinct maximum in February–March of 1.72–2.38 μg m−3 and two minimums in June (0.42 μg m−3) and in September–October (0.36–0.57 μg m−3). 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.

Seasonality of aerosol optical properties in the Arctic

“…This large variability could be attributed to Siberian wildfire events that occur sporadically during the summer, or to the 25 secondary particle formation and growth by biogenic precursors that affect the site sporadically during the summer season (Asmi et al, 2016). Finally, ZEP measures smaller aerosols (larger SAE values) in the spring, and larger aerosols in the late summer, in accordance with the Arctic Haze phenomenon and in agreement with seasonal cycle of SAE at ZEP presented in Pandolfi et al (2017).…”

“…A detailed description of the Tiksi site can be found in Uttal et al (2013) and a previous analysis of aerosols at TIK with a detailed description of the sampling system can be found in Asmi et al (2016). …”

“…The purpose of the IASOA organization is twofold: (1) To enhance interoperable observational abilities and coverage of surface atmospheric monitoring in the data-sparse Arctic, and (2) To foster pan-Arctic scientific collaboration with easier data access and strengthened synergy among researchers (Uttal et al, 2016). Of the 10 monitoring sites, 6 stations have multi-year, continuous measurements of aerosol optical properties, and it is these data from years 2012-2014 that are used for the Arctic aerosol analysis presented in this paper.…”

Measurements of aerosol and CCN properties in the Mackenzie River delta (Canadian Arctic) during spring–summer transition in May 2014

“…This assumption is corroborated by Nguyen et al (2016), who reported comparable yearly cycles of number concentrations and PNSDs from the Villum Research Station in northern Greenland, only differing in more pronounced Aitken modes in the summer months. The shape of the yearly cycle of N CN and the most often occurring PNSDs observed in Tiksi, Russia, described in Asmi et al (2016), were again similar to those observed at Mt. Zeppelin and Alert.…”

Climate Feedback on Aerosol Emission and Atmospheric Concentrations

“…Further recent publications highlight offsetting effects of the different influences but generally agree that rising temperatures lead to increasing BVOC emissions and SOA concentrations. Asmi et al [37] analyze a multi-year aerosol record from an Arctic station in Russia. They also find from the measurements that warmer conditions in Siberia/Russia lead to higher emissions of organic species (as well as more wildfires) and thus cause increasing aerosol concentrations in the Arctic.…”