Asia

Thai rainmakers head for the clouds to combat drought

Thai rainmakers head for the clouds to combat drought
Thailand has carried out 4,000 rainmaking operations this year. Photo: Bangkok Post
Published: 4:00 AM, October 29, 2016

BANGKOK — To take part in a rainmaking mission, one has to forget safety protocol. Pilots refrain from flying into thick clouds to avoid turbulence. But the job of the rainmakers is to do precisely that.

For 32 years, Mr Tawee Kanjana, director of the Royal Rainmaking and Agricultural Aviation Centre for Thailand’s North-eastern Provinces, has been on several hundred such flights as the lead scientist of the operation.

“We run into risky situations sometimes. Once, our three aircraft were caught up in thick clouds without any visibility. Anything was possible,” said Mr Tawee.

“We trust each other’s ability. Our pilots are well-trained. Moreover, we are blessed by His Majesty,” he added, referring to the revered late King Bhumibol Adulyadej, who initiated the rainmaking project in the 1950s to help farmers during droughts. In 2005, he was awarded a patent for weather modification technology.

Mr Tawee said Thailand has carried out about 4,000 operations to make rain nationwide so far this year. “Everything is fine. Besides, 90 times out of 100, we succeed. Science makes miracles,” he said.

Now in management, Mr Tawee does not fly as often as he did. But he still joins the rainmaking missions from time to time.

“I have to be there to make constant updates such as relative humidity value, cloud conditions and any change of wind direction, and I take aerial photographs,” said the 57-year-old scientist.

The rainmakers have other missions. In addition to making rain, they go up to disperse clouds that could lead to hailstorms. They also fly to trigger rainfall to raise water levels in major dams. Before flying, the team studies maps of the area to ensure that rainfall will not affect nearby crops.

Mr Tawee said King Bhumibol’s rainmaking consists of three steps: Triggering, fattening, and attacking the clouds.

Other scientists’ weather modification focuses on the attack process. But the King’s version consists of all three steps to increase the amount of rain because it is feasible in Thailand’s tropical climate.

Rainmaking starts early in the morning. The rainmakers begin with triggering or modifying weather conditions by spreading salt powder at 6,000m, which serves to condense the clouds and attract more moisture.

Around 11am or noon, the team will fatten or expand the size of clouds by spraying calcium chloride or calcium oxide to make the water droplets bigger. Around 2pm, another aircraft will do the attacking. After clouds have been enlarged in a designated area, rainmakers will spray urea or dry ice to drag the clouds lower and create rainfall by cooling the droplets.

The process can usually be completed in one day, but takes meticulous planning and patience.

Mr Tawee, who oversees 20 north-eastern provinces, said scientists float a radiosonde in a weather balloon before an operation to see whether conditions are conducive to rainmaking. Usually, three aircraft are involved in the operation. Sometimes, pilots have to search for clouds for many days.

“We have to be very observant because we are dealing with nature, which can be unpredictable,” Mr Tawee said.

Despite the difficulties and risks, “we are proud that we can overcome the drought by creating raindrops to nourish the hearts of the people”. BANGKOK POST