Exploring the Potential of Cloud Seeding for Rainfall Enhancement

Overview of the Cloud Seeding Experiment

The Indian Institute of Tropical Meteorology (IITM) in Pune has undertaken a groundbreaking cloud seeding experiment in Solapur city, revealing that rainfall could potentially be increased by up to 18%. This experiment is part of the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX), which was conducted over two consecutive monsoon seasons. The findings not only emphasize the scientific feasibility of such interventions but also highlight the economic advantages, estimating a cost of just 18 paisa per litre for the water produced via this method.

Methodology of the CAIPEEX Project

The project, referred to as CAIPEEX phase-4, involved meticulous planning and execution:

• Cloud Selection: A total of 276 convective clouds were identified, with 150 clouds subjected to seeding and 122 serving as a control group.
• Seeding Material: The primary material used for seeding was calcium chloride flare.
• Aerial Resources: Two aircraft were deployed to conduct the necessary operations for the study and seeding process.

Key Findings from the Experiment

The outcomes of the experiment were revealing:

• Effectiveness: The process of cloud seeding resulted in an average rainfall increase of approximately 8.67 mm, translating to about 867 million litres of water.
• Cost-Effectiveness: The initial cost was calculated at 18 paisa per litre, with projections suggesting that this could be halved through the use of indigenous aircraft.
• Limitations: It was noted that not all clouds are suitable for seeding; only about 20-25% of cumulus clouds yielded rainfall when effectively seeded.

Implications of Cloud Seeding

The implications of this research are significant:

• It introduces a novel tool for managing drought conditions and addressing water scarcity challenges.
• The findings set a precedent for the potential implementation of cloud seeding initiatives in other regions facing similar climatic challenges.

Understanding Convective Clouds

Convective clouds are formed due to the upward movement of warm, moist air, a phenomenon known as convection. This occurs when the Earth's surface heats up, causing the air just above to warm and rise. As the air gains altitude, it cools, and the moisture it contains condenses into water droplets, leading to cloud formation. Convective clouds are typically associated with thunderstorm activity and vary significantly in size, from small cumulus clouds to larger cumulonimbus formations that can produce severe weather conditions.

The Role of Aerosols in Cloud Formation

Aerosols are tiny particles or droplets suspended in the atmosphere, which can be natural or anthropogenic. These particles include dust, pollen, soot, and liquid droplets. In terms of climate and weather, aerosols significantly impact the Earth's radiation balance and cloud formation processes. They can either scatter sunlight back into space, resulting in a cooling effect, or absorb it, leading to warming. In the context of cloud seeding, aerosols function as cloud condensation nuclei, providing surfaces for water vapor to condense upon, thereby facilitating cloud development and precipitation.