Field Use of a Simple Technique for Identifying Silver Iodide Particles as Snow Crystal Nuclei

Abstract

A procedure is presented for identifying those silver iodide particles in ice crystals that have behaved as snow crystal nuclei. The new technique is based on the principle that any submicron particle can act as a nucleus in its own superstaurated solution, and can grow to any desired crystal size (the final size depending on time of exposure to the supersaturated solution). For the procedure presented here, an aqueous solution of 30% potassium iodide supersaturated with silver iodide is used. Application of the technique in a weather modification field research project is described. A case-study example is presented, and results of the season's experiments are discussed with emphasis on contributions of the nuclei identification data. It is concluded that the technique has considerable practical utility in qualitative determination of effects from cloud seeding.