ONT

In weather modification programs, ice nucleating materials, and their proper seeding in response to cloud characteristics, control the results. Economical, environmental and technical aspects of existing, or possible future, problems with commonly used nucleants, indicated the necessity of research on alternative seeding materials. The Organic Nuclei Tests (ONT) project consisted of airborne tests of an organic compound, metaldehyde, a inexpensive and biodegradable heterogeneous organic ice nucleant active up to the warmest temperature. The seeding of vapor-activated metaldehyde and that of silver iodide were performed side by side in super cooled stratus decks in the Salt Lake Basin. The seeding tests consisted of two phases; first in the spring of 1981 for visual and photographic documentation of seeding effect, and second in the winter of 1981/1982 with additional cloud physics sensing by the NCAR/NSF QueenAir, B-80.