Health Tips

In the effort to combat the persistent haze that has affected Malaysia and it’s neighboring countries for almost two months now, the government officials have now started to look into cloud seeding operations to induce rain.

The cloud seeding in Malaysia took place at noon on Monday (Sept 16) and has shown “fruitful” results, as rain was reported over several targeted districts, although “ not as much as expected.”

Despite the fact that cloud seeding has gained much popularity recently, many still wonder how it actually works.

What is Cloud Seeding?

Cloud seeding is a weather-modification system that focuses on the process of inducing rain by introducing chemicals into clouds.

3 Cloud Seeding Methods 

1. Static cloud seeding 

• It involves spreading a chemical-like silver iodide into clouds. The silver iodide or dry ice is dispersed into the clouds and provides a crystal around which moisture can condense around. Silver iodide essentially makes rain clouds more effective at dispensing their water.

2. Dynamic Cloud Seeding

• This method of cloud seeding aims to boost vertical air currents, which encourages more water to pass through the clouds, resulting in more rain. Compared to the static method, dynamic cloud seeding requires up to 100 times more ice crystals, making it not only more complex but also less dependable than its other counterpart.

3. Hygroscopic Cloud Seeding

• This technique involves the dispersion of salts through flares or explosives in the lower portions of clouds. As water joins with them, the salt grows in size. Although hygroscopic cloud seeding holds much promise, it would still require further research.

How Do They Do it in Malaysia?

Chemicals are released from the aircraft into the clouds below. A common substance used is silver iodide (Static Cloud Seeding), other than substances such as dry ice, calcium oxide, propane, and butane. 

The chemical particles mimic the function of ice crystals so that water condenses around them. So when water droplets condense around ice crystals in the sky, clouds will start to form, increasing the likelihood and amount of rain to fall. Rain falls when the clouds hold too many water droplets.

What Are The Dispersal Methods

The silver iodide or dry ice can be delivered by:

a) Airplane flares

Flares mounted on airplane wings spray the chemicals across clouds

b) Rocket

Rockets are launched into the clouds and release the chemicals

c) Generator

Silver iodide is sprayed into a propane flame, which is then transported by the heat and wind.

How Effective is Cloud Seeding?

Cloud seeding so far has been successfully shown to create water droplets in the clouds, but the air under the clouds is often too dry, which causes evaporation before the rain hits the ground. So cloud seeding may work but the results so far have been largely disappointing.

Malaysian officials admit that rainmaking is only a temporary fix for the regional health crisis and that we must address the source that caused the haze in order to fully tackle this haze problem on the international level. 

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References:

1. Chew, H. (2015). Malaysia and Indonesia begin cloud seeding to fight haze: How cloud seeding works. [online] The Straits Times. Available at: https://www.straitstimes.com/asia/se-asia/malaysia-and-indonesia-begin-cloud-seeding-to-fight-haze-how-cloud-seeding-works.

2. AsiaOne. (2019). Tackling the haze: How does cloud seeding work?. [online] Available at: https://www.asiaone.com/health/tackling-haze-how-does-cloud-seeding-work.

3. HowStuffWorks. (2019). Can China control the weather?. [online] Available at: https://science.howstuffworks.com/nature/climate-weather/meteorologists/cloud-seeding1.htm

4. TEOH, S. (2019). Cloud seeding yields rain over Kuala Lumpur and nearby states in Malaysia. [online] The Straits Times. Available at: https://www.straitstimes.com/asia/se-asia/cloud-seeding-yields-rain-over-kuala-lumpur-and-nearby-states-in-malaysia.

5. YouTube. (2019). Malaysia cloud seeding to counter haze from Indonesian forest fires. [online] Available at: https://www.youtube.com/watch?v=xfGnZAgZ8PU&t=41s

Image credit:

1. https://efficientgov.com/wp-content/uploads/2015/05/cloud-seeding.jpg

2. https://imagevars.gulfnews.com/2019/01/06/MAKING_RAIN_THROUGH_ARTIFICIAL_MEANS_resources1_16a3106b7b1_original-ratio.jpg

3. https://max.nwstatic.co.uk/newsimages2016/weekly/20170415/generator.png

Written by

Dr. Jeanrette J. Nierras