Concentration and size variation of condensation nuclei at Mawson,Antarctica

Condensation nucleus (CN) concentrations have been measured at Mawson (67.6°S, 62.9°E) since mid 1981. Weekly median concentrations have an annual cycle with a maximum of around 300 to 400 cm^-3 in summer and a minimum of a few tens of particles per cm^-3 in winter. In this respect Mawson behaves very much like an Antarctic continental location. Preliminary measurements of the size distribution of CN particles taken over a nine month period suggest a seasonal change in typical particle radius from around 0.01 m in winter to around 0.04 m in summer. Diurnal variation in the CN concentration is generally very weak and does not show any systematic relation to the pronounced diurnal variation in wind-speed at Mawson.Department of Science, Antarctic Division