Properties of the stratospheric aerosol

Abstract

Studies of the chemical composition, size distributions and concentrations of stratospheric aerosol particles have shown that the particles consist of ammonium sulfate and ammonium persulfate, and may have liquid associated with them in the stratosphere. The average particle size distribution function was found to approximate a log-normal distribution over the range of radius 0.1 to 1.0 microns. The number concentrations found were variable but generally of the order of 0.05 cm−3 at 18 km altitude. The corresponding mass concentrations are of the order of 10−2 pg cm−3. Combination of the presently determined size distribution with estimates of the size distribution of Aitken nuclei in the stratosphere indicates that the overall distribution of partculate matter in the lower stratosphere may be bimodal. This bimodality indicates that other processes in addition to coagulation must occur if the particles with radius < 0.1 micron give rise to particles with radius > 0.1 micron.DOI: 10.1111/j.2153-3490.1966.tb00259.x