AEROSOL OBSERVATIONS IN THE SIBERIAN ARCTIC

Atmospheric concentrations of total particulate mass (TPM) and aerosol chemical species were measured at three sites in the Siberian Arctic; Tiksi, Norilsk and Yakutsk. Continuous samplings of aerosols were carried out from August 1993 in Norilsk and Yakutsk, and from August 1994 in Tiksi. Tiksi is located on the coast of the Laptev Sea connecting to the Arctic Ocean. Norilsk is located at the base of the Taimyr Peninsula, which is the largest single sulfur dioxide emission source in the world. Yakutsk is situated on the middle reaches of the Lena river. Measured concentrations of the main aerosol chemical species at Tiksi ranged from 0.06-0.3μ(gm)^ for elemental carbon, 0.55-1.5μ(gm)^ for organic carbon and 0.09-1.6μ(gm)^ for SO_4^. The measured sulfate and elemental carbon concentrations showed remarkable seasonal variations with winter maxima and summer minima. The seasonal variations were consistent with other studies of Arctic haze in the Alaskan, Canadian and Norwegian Arctic. There were no significant seasonal variations of pollutant concentrations at Norilsk and Yakutsk. The TPM ranged from 6 to 30μ(gm)^ at Norilsk and from 7 to 39μ(gm)^ at Yakutsk. Major aerosol composition was sulfate at Norilsk, and carbonaceous particles at Yakutsk. We also performed trajectory analyses of air parcels to estimate the potential source regions which caused elevation of pollutant concentrations in winter at Tiksi. We calculated 10-day backward trajectories at Tiksi and forward trajectories at Norilsk in 1994. According to the calculations, the pollutants which arrived at Tiksi were frequently transported from Norilsk, the Urals and other source areas in winter. Further, it was suggested that Norilsk was one of the source areas for Arctic haze