Aerosol size distribution seasonal characteristics measured in Tiksi, Russian Arctic

Abstract

Four years of continuous aerosol number size distribution measurements from an Arctic Climate Observatory in Tiksi Russia are analyzed. 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 μgm-3 and two minimums in June of 0.42 μg m-3 and in September-October of 0.36-0.57 μgm-3. These seasonal cycles in number and mass concentrations are related to isolated aerosol sources such as Arctic haze in early spring which increases accumulation and coarse mode numbers, and biogenic emissions in summer which affects the smaller, nucleation and Aitken mode particles. The impact of temperature dependent natural emissions on aerosol and cloud condensation nuclei numbers was significant. Therefore, in addition to the precursor emissions of biogenic volatile organic compounds, the frequent Siberian forest fires, although far are suggested to play a role in Arctic aerosol composition during the warmest months. During calm and cold months aerosol concentrations were occasionally increased by nearby aerosol sources in trapping inversions. These results provide valuable information on inter-annual cycles and sources of Arctic aerosols.