Bangkok - The Royal Thai Air Force has launched an attack on the weather this week, sending two German-made Alpha Jet fighters and other aircraft into the clouds to make rain, media reports said Wednesday.

Air force chief Itthaporn Subhawong said the two Alpha Jets along with 13 other aircraft were deployed Tuesday as part of the annual rain-making mission for the kingdom, the Bangkok Post reported.

The German-made fighters have been armed with silver iodide bullets that release rain-making substances when fired into clouds at 6,100 metres.

This year's rain-making mission, conducted during the hot season from March to May, would also use six AU-23 fighter planes, four BT-67 aircraft and three NOMAD transport planes, Ittaporn said.

Last year, the air force operated 618 rain-making flights, releasing 900 tons of chemicals into the clouds.

Artificial rain-making was an initiative of Thai King Bhumibol Adulyadej as part of his agricultural development efforts.

The missions have a success rate of 85 to 95 per cent, according to the Bangkok Post. (dpa)