Aerosol size distributions in the southwest Pacific

Measurements of the size distribution and concentration of the atmospheric aerosol were made from an instrumented aircraft at altitudes of up to 6 km around New Zealand (37°S to 46°S) and during flights to other southwest Pacific islands (to 9°S). Measurements were also made at the surface in Antarctica (78°S). Single‐particle optical counters were used to cover the size range 0.06 μm to 8.0 μm radius. The results show that the free troposphere aerosol concentration ranged from 1.8 to 46 cm−3 and the size distribution was characterized by a “Junge” slope around −3.5. In the planetary boundary layer, including Antarctica, the concentrations were generally greater and more variable, and the size distributions often bimodal.