There are two main types of cloud seeding:
Static Seeding: This method is used to increase precipitation from supercooled clouds. Supercooled clouds are clouds that contain water droplets that are below freezing but have not yet frozen. Static seeding involves dispersing silver iodide or dry ice into clouds. These substances act as ice nuclei, providing a surface for water droplets to freeze. Once water droplets freeze, they can grow larger and eventually fall as rain or snow.
Dynamic Seeding: This method is used to increase precipitation from convective clouds. Convective clouds are clouds that form due to the rising of warm air. Dynamic seeding involves the dispersion of hygroscopic salts, such as sodium chloride, into clouds. These salts absorb water vapor and grow in size. Once the salt particles are large enough, they fall as rain.
Here is a step-by-step overview of the artificial rain process:
Identify the correct clouds. Clouds that are already producing rain or snow are generally not suitable for cloud seeding. Instead, scientists look for clouds that are likely to produce rain but are not yet doing so.
Disperse the seeding agent into the clouds. This can be done using aircraft, ground generators or rockets.
Monitor the results. Scientists observe clouds after sowing seeds to see if rain is produced. If precipitation occurs, it measures the amount of precipitation and the area it covers.
Cloud seeding is a complex process and its effectiveness is still debated by scientists. However, it has been used successfully in some parts of the world to increase rainfall and reduce the risk of drought.
Here are some examples of where artificial rain has been used:
In 2008, China used cloud seeding to increase rainfall during the Beijing Olympics.
In 2010, the United Arab Emirates used cloud seeding to increase rainfall in the country's desert regions.
In 2014, the United States used cloud seeding to increase rainfall in California during a drought.