The Influence of Meteorological Conditions on Rainmaking in the Sydney Area

Abstract

An analysis is presented of the results of 88 flights whose purpose was to carry out rainmaking experiments, using dry ice, in the Sydney area between January 1948 and June 1950. The chance of encountering clouds suitable for rainmaking is shown to be correlated with the synoptic situation, the water content above the freezing level, the height of the freezing level, and the lapse rate below lt. The number of days on which rainmaking was possible in the Sydney area is estimated as 45, 33, and 8 for 1948, 1949, and January to June 1950 respectively, a smaller number of opportunities occurring when the natural rainfall was abnormally high. The possibility of forecasting days suitable for rainmaking is examined.