Type I polar stratospheric cloud particles - Concentration, shape, size, light extinction

Results from the flight on January 24, 1989 of the Airborne Arctic Stratospheric Experiment during which the ER-2 aircraft transitioned from unsaturated to ice saturated air at 20 km altitude are presented. Aerosol particles were sampled by wire impactors and examined for number density as a function of particle size by taking photomicrographs in a scanning electron microscope and visually sizing and counting the particles. Differences in the chemical, physical and optical properties of stratospheric aerosol between ice-saturated and nonsaturated air are described.