Large aerosol particles in a convective storm environment

Concentrations of large (d > 10 μm) inorganic and organic particles varied widely at ground level and at subcloud altitudes. Particle concentration decreased at a slower rate aloft than at ground level; as a result, the relative abundance of large aerosol particles aloft tended to increase with increasing particle size. A substantial fraction of organic particles aloft was found to be responsible for this trend.

Curves of freezing frequency indicate the presence of two distinctive sources of freezing nuclei derived from large aerosol particles active in the − 9 to − 12°C and − 19 to − 22°C temperature ranges.