Measurement of the Stratospheric Aerosol Particle Size Distribution.

A white light photoelectric aerosol detection system suitable for free atmospheric determination of particle concentration from ground level to about 28 km altitude is described. Particle size distributions obtained in situ over the radius range of approximately 0.16 to 1 m on three soundings are presented. The tropospheric distributions show close to power-law dependence, dN/dlogr=r^3.3, whereas the stratospheric distributions have a steeper power law slope for r0.3 m and a flatter slope for r0.3 m, agreeing well with a recent impactor-derived distribution using a new analysis model. These findings question the validity of earlier globally representative distribution models.