The Structures of Summer Convective Clouds in Eastern Montana. II: Effects of Artificial Seeding

Abstract

The seeding of clouds in Miles City, Montana with AgI pyrotechnics at cloud tops generally produced large increases in ice particle concentrations, decreases in liquid water contents, and increases in precipitation particles lower down in the clouds. Similar, but even more pronounced, changes were observed when clouds were seeded with dry ice. Seeding with AgI-NH4I-acetone solution at cloud base generally did not produce observable changes in cloud microstructures at higher levels but in one case changes attributable to this type of seeding were observed. Comparisons of the structure of seeded clouds at Miles City with unseeded clouds suggests that the seeding of small and embedded cumulus clouds with dry ice to produce ice panicle concentrations of ?1?10 ??1 may offer the best potential for enhancing precipitation.