Terpene-Iodine Compounds as Ice Nuclei

Abstract

Silver iodide particles deposited on vegetation may photolyse and combine with natural terpenes from tree oils to form compounds which either themselves become aerosols, or become attached to aerosol particles. In either case the new compounds may become active centers acting as freezing nuclei. Silver iodide particles may persist for several months when deposited on coniferous trees, and may release variable doses of such freezing nuclei during that time. Although the concentrations of ice nuclei so produced are probably too small to influence precipitation, they may nevertheless contaminate large areas and thus may be significant for long-range research programs concerned with measuring natural concentrations of freezing nuclei.