Malaysia and Indonesia begin cloud seeding to fight haze: How cloud seeding works

A worker stands as the haze shrouded Batanghari River in Jambi, on Indonesia's Sumatra island, on Sept 15, 2015.
A worker stands as the haze shrouded Batanghari River in Jambi, on Indonesia's Sumatra island, on Sept 15, 2015. PHOTO: REUTERS

SINGAPORE - After days of persistant haze, Malaysia was to begin cloud seeding operations at noon on Tuesday (Sept15).

Schools were shut in several states as dozens of areas in Malaysia recorded unhealthy air quality readings.

In Indonesia, a state of emergency was declared in Riau province on Monday, and aircraft have been deployed to water-bomb the fires, and conduct "cloud seeding" to induce rain.

Here's how cloud seeding is done:

 

WHAT IT IS

Cloud seeding is the induction of rain by introducing chemicals into clouds.

Silver iodide or dry ice is dispersed into the clouds, and provide nuclei for moisture to condense around.

WHY IT WORKS

Water in the clouds is supercooled to ice when it bonds with the silver iodide, which has a similar crystalline structure to ice.

When too heavy to remain suspended, the ice crystals fall, and melt on the way to become rain.

DISPERSAL METHODS

The silver iodide or dry ice can be delivered by:

* Airplane flares

Flares mounted on airplane wings spray the chemicals across clouds

* Rocket

Rockets are launched into the clouds and release the chemicals

* Generator

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

SOURCES: REUTERS, AFP, THE STAR, PHYSICS.ORG