Cloud Seeding

• Context (TH | TOI): Cloud seeding experiment in Solapur of Maharashtra resulted in 18% more rainfall than normal conditions.

• Solapur falls on the leeward side of the Western Ghats and hence normally gets low rainfall.
• Cloud seeding is a weather modification technology that artificially stimulates rainfall by spraying chemical substances into the air that serve as cloud condensation nuclei.
• Cloud condensation nuclei are small particles upon which water vapour condenses to form clouds.
• The chemical substances used are silver iodides, potassium iodides, dry ice (solid carbon dioxide) or liquid propane.
• It works only when there are enough pre-existing clouds in the atmosphere.

Different Cloud Seeding Methods

• Hygroscopic Cloud Seeding: Salts are sprayed through explosives in the lower portions of clouds.
• Static Cloud Seeding: Chemicals like silver iodide crystals are sprayed into clouds.
• Dynamic Cloud Seeding: Vertical air currents are boosted to encourage more water to pass through the clouds which translates into more rain.

Applications of Cloud Seeding

• Increases rainfall
• Regulates weather: Creates favourable microclimates by dispersing fog, suppressing hail, and modifying cyclones.
• Controls air pollution and water pollution

Limitations of Cloud Seeding

• Cannot mitigate drought: It can simply partially address the water requirements.
• Cannot produce rainfall from all clouds.

Challenges in Cloud Seeding

• Cause abnormal weather conditions: For e.g., when naturally less moisture place receives more rainfall, then it may cause flash floods.
• Harmful for environment and health: Chemicals used in cloud seeding are toxic.
• Contribute to global warming: The chemicals used in cloud seeding are a source of GHGs.