The Disposition of Silver Released from Soviet Oblako Rockets in Precipitation during the Hall Suppression Experiment Grossversuch IV. Part I: Measurements of Background and a Preliminary Seeding Test

Abstract

Abstract In association with Grossversuch IV, a program designed to test the Soviet hail suppression method by seeding clouds with AgI from Oblako rockets, a complementary program was conducted by l'Observatoire du Puy-de-Dome and the Desert Research Institute to study the diffusion of the seeding material (AgI) in the clouds, based on the analysis of silver in precipitation. This program covered the summers of 1977 and 1978, and this paper describes the results of measurements of natural background silver concentrations in unseeded precipitation. It also describes a new automatic precipitation collector, five of which were first tested in the field in 1977. A more extensive network of 15 collectors was deployed during two months of the 1978 summer. Based on the analysis of 118 unseeded precipitation samples collected in 1977, the natural background concentration of silver was estimated as 0.9 × 10−11 g mL−1(σ = 0.6 × 10−11 g mL−1). Although the standard deviations overlap, the 1978 season results appear ...