Intraseasonal factors responsible for the variability of aerosol and ion content in the polar regions of the atmosphere

The dispersion of aerosols with particle diameters varying from 0.004 to 10 mu m, their elemental composition, and the spectrum of atmospheric ion mob ility in the range between 0.00032 and 5 cm(2)/(V s) were measured in the a tmospheric surface layer on Tsigler Island (western Arctic, Franz Josef Lan d, spring 1994). The measured data are reported and correlated with our dat a obtained using similar methodology and instruments on Wrangel Island (eas tern Arctic, spring 1985), the Laptev Sea (summer 1995), the Antarctic cont inent (Mirnyi and Molodezhnaya observatories, 1984 and 1992), in the Pamirs (Fedchenko glacier, autumn 1989), and the Moscow region (Obninsk, spring 1 994). These results provided new information on the factors responsible for the variability of polar aerosols and air ions. Size-dependent spectra of aerosols over extended snow-covered areas are con servative with respect to variations in relative humidity, solar, gamma, an d beta radiation, and wind direction. Moderate and high winds (from 8 to 30 m/s) stimulate an increase in the number density of the particle fraction with diameters D from 0.5 to 1 mu m and of large particles (D > 3 mu m). Fi ne particles (D < 0.1 mu m) only slightly depend on variations of the wind speed; on the contrary, hard frosts (temperature T from -20 to -35 degrees C) stimulate their number density to increase without regard to the wind sp eed. Over the polar seas, humidity above 85% initiates hazes whose droplets fall predominantly into the size range from 3 to 5 mu m. During the spring reconstruction, the number density of aerosol particles with D > 0.5 mu m is increased by a factor of 5 to 10. In comparison with the Antarctic region, the air basin of the Arctic region in spring is more heavily polluted by particles of all sizes from the rang e D = 0.075-5 mu m. The pollution of the snow cover appears comparable and, with respect to some elements, lower than the corresponding pollution in t he adjacent Norwegian Arctic. The aerosol pollution in the western (Franz J osef Land) and eastern (Wrangel Island) portions of the Russian Arctic is c lose in metal content to that of the Canadian Arctic. By and large, no tend ency toward an increase in the pollution of the arctic air and snow cover w as observed in the most recent 15-20 years. It is the cooled polar atmosphere that supplies the aerosol substance in th e form of very fine (D < 0.01 mu m) and large (D > 2 mu m) particles. Most likely, these particles are generated during gaseous-phase reactions.