CLOUD SEEDING AND ITS TECHNIQUES

                                                    CLOUD SEEDING 

What is cloud seeding?

 

Cloud seeding is the weather modification technique that improves a cloud’s ability to produce rain or snow by introducing tiny ice nuclei into certain types of sub freezing clouds.

 

How rain is formed? 

Rain is liquid precipitation falling from sky. When a small droplets bumps into a bigger one, it condense and becomes heavier. When water droplets is heavier, continue to float in the cloud, it falls to ground as rain. 

Cloud seeding is artificial Rain technology. Cloud seeding uses planes to spray clouds with chemical to condense smaller particles into larger rain droplets. By using this technology rate of rainfall increases by 10% t 30% per year and this operations cost much less than the desalination process.

Founder of cloud seeding technique:

 

An American chemist and Meteorologist VINCENT JOSEPH SCHAEFER, researcher at the General Electric Laboratory developed cloud seeding. On November 13, 1946, first experiment was conducted in the Berkshire Mountains by seeding the cloud with dry ice and silver iodide, an inorganic compound to improve the creation of ice crystal in cloud. He was issued 14 patents.

 

How cloud seeding works?

Cloud consists of water droplets or ice crystals. The chemical silver iodide is freed into the atmosphere to amplify the water amount in the air in order to create fog, precipitation and hail. Silver iodide has a hexagonal structure that aids clouds to freeze. The cloud seeding is the process of spreading either dry ice or silver iodide aerosols into upper part of the clouds to try to stimulate the precipitation process and form rain. After cloud seeding takes places, the newly formed snowflakes quickly grow and falls from the cloud back to the surface of earth, increasing snow pack and stream flow.

 

Cloud seeding Techniques:

There are few principal cloud seeding techniques adopted 

STATIC METHOD: 

Discovered by the atmospheric scientist Dr. William R .Cotton. With the help of aero planes, they spread silver iodide, ice nucleating agents at the base of the clouds. The silver iodide interacts with the moisture in the cloud and act as ice crystal because of the hexagonal crystal in silver iodide. It causes rain. It requires a specific condition such as -20˚to-4˚c temperature. It is most advanced techniques used in recent days.

DYNAMIC METHOD:

It is a more complicated process than the static method since it employs 100 times more cloud seeding agents and has 11 phases to promote cloud precipitation. 

HYGROSCOPIC METHOD:

Near the base of the clouds, explosive hygroscopic are distributed mechanically. Hygroscopic salts have a diameter that varies from 5 to 100 micrometers, expand in size through vapor, and produce rain by impact. 

GLACIOGENIC METHOD:

Ice formation in super cooled clouds is to be sparked by glaciogenic, resulting in precipitation. Glaciogenic processes often involve distributing effective ice nuclei into clouds, such as silver iodide, where they lead to heterogeneous ice nucleation. Another option is to employ liquid carbon and causes super cooled water droplets to freeze uniformly. 

PURPOSE OF CLOUD SEEDING: 

• Induce more rainfall and snowfall and lead to more mountain snowpack. 
• Enhance the natural water supply. 
• Boosting of the economy, improve the agriculture production, proper harvest, betterment of living. 
• Weather regulation, lessen hailstorm by reordering water vapor in clouds, which breaks down large hailstone. 
• It helps in production of hydroelectricity in Tasmania, Australia. 
• Used to settles down toxic air pollutants through rain, reduce pollution (e.g. tackle Delhi’s air pollution). 
• Enhance rainfall in dry deserted areas. Make land fertile and promote tourism. 

NEGATIVE IMPACT: 

• Uses of chemicals sometimes cause harmful to the natural environment. 
• It is expensive. 
• Specific atmospheric condition is need for cloud seeding. Not all cloud gives positive result. 
• Unpredictable weather patterns, it may lead flooding. 
• It is not proven to be effective. 
• Negative impact on weather forecast. 
• Exposure of chemical may cause skin problem like argyria. 

COUNTRIES USING ARTIFICAL RAIN TECHNOLOGY: 

•  China which has world’s largest cloud seeding system . 
•  Thailand 
•  Mumbai located in India 
•  Dubai located in UAE 
•  Australia, Chile, France , Greece, Israel, Spain 

 52 and more countries have cloud seeding programs, performed by 34 private weather modification companies. 

CONCLUSION: 

Cloud seeding aims to change a cloud’s natural evolution in order to increase precipitation, decrease hail, clear the air of fog, or lessen lighting. Despite having a significant number of positive effects, it also has unknowable risks, making it an unreliable option.

REFERENCES:

https://www.britannica.com/science/cloud-seeding

https://futureofworking.com/8-advantages-and-disadvantages-of-cloud-seeding/