A Cloud-Seeding Experiment in the Snowy Mountains, Australia

View More View Less
  • a Commonwealth Scientific and Industrial Research Organization, Radiophysics Laboratory, Sydney, Australia
  • | b Snowy Mountains Hydro-Electricity Authority, Cooma, N.S.W. Australia
© Get Permissions
Full access

Abstract

A cloud-seeding experiment was conducted in the Snowy Mountains of Australia from 1955–1959 inclusive. The objective was to determine if silver-iodide smoke released from an aircraft into clouds could increase the precipitation over a selected area. The method involved a comparison of the precipitation in a target area and that in a control area during randomized periods of seeding and no seeding. Over the five years, the ratio of the precipitation in the target to that in the control area was higher in seeded than in unseeded periods. Three statistical tests are presented which show that the seeded periods are different from the unseeded periods at significance levels of 0.03, 0.09 and 0.03 (one sided). This supports a positive seeding effect. Other analyses both detract from and support this contention. The net result is that the experiment in inconclusive. Further, improved experiments are proposed.

Abstract

A cloud-seeding experiment was conducted in the Snowy Mountains of Australia from 1955–1959 inclusive. The objective was to determine if silver-iodide smoke released from an aircraft into clouds could increase the precipitation over a selected area. The method involved a comparison of the precipitation in a target area and that in a control area during randomized periods of seeding and no seeding. Over the five years, the ratio of the precipitation in the target to that in the control area was higher in seeded than in unseeded periods. Three statistical tests are presented which show that the seeded periods are different from the unseeded periods at significance levels of 0.03, 0.09 and 0.03 (one sided). This supports a positive seeding effect. Other analyses both detract from and support this contention. The net result is that the experiment in inconclusive. Further, improved experiments are proposed.

Save