Abstract
Scientifically-based methods of rainmaking (one of planned weather modification technologies) appeared brilliantly just after World War II, and are currently used in about 40 nations and regions worldwide. The rainmaking methods introducing dry-ice pellets or artificially generated aerosols which act as cloud condensation nuclei and/or ice nuclei into clouds, bypass the rate-limiting processes in rain and snow formation mechanisms in natural clouds by producing precipitation embryos in the form of large droplets in warm clouds or ice crystals in cold clouds, and lead to precipitation enhancement. In this paper, while describing the necessity, history, principle and problems of rainmaking, the leading-edge trend of the planned weather modification research is briefly introduced.
