posted on May, 4 2004 @ 11:00 PM
Sigh (please read before asking stupid questions)
“Rainmaking 1939 - 1972
Wartime work on radio wave propagation led to an extended study by Dr E.G. Bowen of atmospheric behaviour and cloud physics. It was suggested in the
USA that if a seeding agent were intoduced into supercooled clouds of water droplets, tiny ice crystals would be formed, collect water droplets and
fall from the cloud. Within a few weeks of the announcement, field experiments were in progress. Australia quickly became a leader in cloud physics
research and the techniques of artifical stimulation of rainfall. Scientists from India, Pakistan, the Philippines, Korea, Israel, Singapore, USA,
Egypt, Malaya and Chile came to study at the Laboratory or to use the Australian methods.
In October 1952 a rainmaking Dakota aircraft disappered in cloud off Cronulla. Laboratory scientists R.S. Styles and F.W. Campbell and the whole
R.A.A.F crew lost their lives."
"2.1 Early CSIRO Single Cloud Experiments
Cloud seeding experiments began in Australia in 1947, shortly after the classic experiments of Schaefer (1946) in America showing that pellets of dry
ice could rapidly glaciate a laboratory cloud. The first cloud seeding trials were carried out by Kraus and Squires (1947) near Sydney. In these and
subsequent experiments from 1947 to 1952 scientists in the CSIRO Division of Radiophysics used Royal Australian Air Force aircraft (mostly Liberators,
Beaufighters and DC3s) to drop dry ice into the tops of cumulus clouds. The conclusion reached from these experiments was that the method worked
reliably and initiated rain that would not have otherwise occurred. However, the success of the rain-making was determined by the temperature of the
cloud top. Below -7°C there was a 100% chance of producing precipitation, but at temperatures of -15°C and cooler the results lose their significance
because of the high probability of naturally occurring rain (Bowen, 1952)."