CONDENSATION NUCLEUS SIZE DISTRIBUTION AT MAWSON, ANTARCTICA - SEASONAL CYCLE

The size distribution of atmospheric condensation nuclei (CN) has been measured at Mawson, on the Antarctic coast, during the period 1985-19 90. A clear seasonal cycle is demonstrated in the size distribution wi th periods of marked bimodality during early spring and autumn. Betwee n these periods, in late spring and summer, steady growth in particle size followed by a period with a relatively stable size distribution a nd relatively little new particle production were observed. During the remaining part of the year nucleus mode particle concentrations were low, typically less than 20 cm-3.