The science behind cloud seeding

Cloud seeding is also known as 'artificial rainfall.' It is the technique to increase the chances of rainfall according to the weather condition. A big cloud crystal or water droplets are encouraged to form, which results in rainfall or snowfall.

History:

Artificial rainfall began with experiments by Vincent Schaefer in 1946. The technique discovered dry ice when introduced to cloud-induced precipitation.

The process:

• Cloud identification

• Seeding agent selection: Silver iodide, potassium iodide, and dry ice are condensation nuclei or ice nuclei.

• Agent Dispersion Method: Via Aircraft.

• Cloud Enhancement: The formation of ice crystals or water droplets.

• Precipitation Initiation:

Chemicals like silver iodide, potassium iodide, and dry ice are released into the sky using airplanes and helicopters. These chemicals attract water vapor, leading to the formation of rain clouds. It usually takes about half an hour for this method to make it rain.

There are 2 types of cloud seeding:

1) Hygroscopic cloud seeding

Aims to accelerate the coalescence of droplets in liquid clouds, resulting in the formation of larger droplets that lead to precipitation.

Salt particles are typically dispersed at the cloud's base.

2) Glaciogenic cloud seeding

Inducing production in supercooled clouds, leading to precipitation.

Involves dispersing efficient ice nuclei, such as silver iodide particles or dry ice, into the cloud, which triggers heterogeneous ice nucleation.

Delhi air pollution and cloud seeding

• Delhi-NCR air pollution is planned to be tackled by artificial rain.

• The pollution in Delhi is at a severe stage, causing significant problems for its residents and surroundings.

• The aircraft releases a mix of silver iodide, iodide salt, and rock salt into the specific nimbostratus clouds at the altitude between 500 and 6,000 meters.

• Artificial rain could provide temporary relief for up to a week to residents in Delhi suffering from poor air quality.

Advantages:

The main reason for cloud seeding is to increase precipitation in crucial areas facing water shortages or drought conditions.

• Agricultural:

  • support yields and agriculture during drought-like weather conditions.

• Wildfire preclusion

  • Artificial rain can be used to dampen dry conditions or reduce the risk of fire spreading.

• Hydroelectric power

  • It impacts water level and increases water levels. Beneficial for generating hydroelectric power.

Disadvantages:

• Low risk,

• concerns about their long-term effect on the ecosystem.

• Dynamic and uncertain weather conditions.

• Ethical concerns

• Cost

• Used in China and Middle Eastern countries for many years.

• More than 50 countries use this technology.

• China has used several times to combat pollution.