What kind of weather conditions are needed for artificial rainfall?

Artificial rainfall should have sufficient conditions. Generally, natural precipitation requires not only certain macro weather conditions, but also microphysical conditions in the cloud, such as: there must be large water droplets in the warm cloud above 0℃; There should be ice crystals in Leng Yun below 0℃. Without this condition, no matter how good the weather is or how good the clouds are, it won't rain. But in natural circumstances, this microphysical condition is sometimes not available; Sometimes, but not enough. The former will not produce precipitation at all; The latter has less rainfall. At this time, if artificial ice cores are planted artificially in the cloud, the process of ice water transformation will occur in the cloud, and then with the help of the natural collision process of water droplets, rainfall can be generated or increased.

Artificial rainfall is an effective means to develop and utilize air water resources. Its core is to exert a catalytic effect on local atmospheric clouds through transmission means such as airplanes, cannons and rockets, so that more water in the clouds falls into raindrops. At present, there are usually three kinds of catalysts used in artificial rainfall: the first kind is hygroscopic agent such as salt particles, which can absorb water in the cloud and turn it into larger water droplets; The second is dry ice with extremely low temperature, which can cool the surrounding air layer to about MINUS 40 degrees Celsius when evaporating, thus causing condensation of water vapor; The third catalyst is silver iodide called "nucleating agent", which has the nature of natural ice nuclei in clouds.