[FOCUS] S. Korea to conduct first offshore artificial rain experiment

By Lim Chang-won Posted : January 23, 2019, 15:48 Updated : March 7, 2019, 12:46

[Yonhap News Photo]

SEOUL --​ South Korea will conduct its first offshore experiment this week to see if artificial rainfall is effective in alleviating air pollution caused by fine dust, which has been a source of prime public concerns and diplomatic disputes in Northeast Asia.

The experiment will be carried out on Friday by the Korea Meteorological Administration (KMA) in the Yellow Sea. Flying at a speeds of more than 350 kilometers (217 miles) per hour, a plane will spray 24 rounds of silver iodide, a chemical used to create rain clouds. KMA resesearcher would observe cloud and precipitation changes with a satellite and weather radars

"If the effect of artificial rainfall is proved scientifically, we will carry out further research to make practical use of artificial rainfall technology, which is still in the basic research stage," KMA administrator Kim Jong-seok told reporters. An exact location would be disclosed later.

Artificial rain has been used mainly to cleanse the air by using cloud seeding, a specific form of weather manipulation which aims to replicate the effects of rainclouds in dry, polluted or smoggy regions.

The first stage involves chemicals released into the air to stimulate air mass and form rain clouds. In the next stage, chemicals such as ammonium nitrate or calcium chloride are injected to act as a catalyst and enlarge the size of clouds. Finally, chemicals like silver iodide or dry ice are used to destabilize the cloud and formulate water droplets.

China and India have used artificial rainfall to improve air quality. In August 2008, Beijing used artificial rainfall to ensure a dry night for the Olympic opening ceremony.

There are still doubts over the efficacy of artificial rain as a fundamental way of fighting air pollution. A research center run by Kangwon National University's department of biological environment found that at least five millimeters of rain per hour should be used to reduce the concentration of fine dust.

"When the high concentration of fine dust occurs, it is difficult to generate a rainfall because our country is under the influence of high pressure, and technological limitations make it difficult to produce enough rain to wash away fine dust," said Joo Sang-won, director-general of the state-run National Institute of Meteorological Sciences.

At a cabinet meeting on Tuesday, President Moon Jae-in directed government officials to handle fine dust as a national policy objective like a natural disaster. "It's time to take special measures by demonstrating creativity and imagination," Moon said, urging government officials to work out special steps and develop technologies such as artificial rainfall, air filter purification and dust collectors.

Moon also called for cooperation with China to discuss joint measures and set up an early warning system. "I know well that there are great public concerns about fine dust coming from China."

Fine dust refers to particles smaller than 10 micrometers and causes various respiratory problems. China has been cited in South Korea as the main culprit for aggravating particulate pollution on the Korean peninsula, but experts also point to power plants and vehicles using fossil fuel. Seoul and Beijing have discussed practical steps to bring down levels of fine dust particles and harmful volatile organic compounds (VOCs).

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