How can I stop the rain?
Conditions of precipitation formation
There are two conditions to form precipitation, one is that there should be enough water vapor in the cloud, and the other is that there should be an appropriate number of condensation nuclei. Therefore, the method of artificial rainfall is to introduce artificial condensation nuclei into the cloud. Generally, aircraft, rockets, anti-aircraft guns, balloons and ground burning silver iodide in the updraft area are used to send the catalyst into the cloud.
Planes usually fly to an altitude of about 6000 meters and spread catalysts through clouds. Rockets and anti-aircraft guns directly bombard the appropriate parts of thunderstorm clouds, and the warheads are loaded with silver iodide and sent into the clouds.
Under the balloon hung a silver iodide flame bomb, which rose above the zero layer of the cloud and burned, releasing the catalyst. Generally, it is hygroscopic substances such as salt powder, urea and calcium chloride. Used for warm clouds above zero, making the water vapor in the clouds turn into water and drop into rain.
For Leng Yun where the temperature is below zero, artificial crystal nucleus silver iodide, or dry ice and liquid nitrogen should be sown to increase the number of ice crystals in Leng Yun and improve the precipitation efficiency.