As an agrarian country where the majority of people are connected in some way with agriculture, Thailand needs high levels of water for farming purposes. Since most Thai farmers have to wait for seasonal rain to grow crops, they are at times faced with difficulties from drought, so there might not be enough rainfall for crop growing. During his travels to every corner of the kingdom to visit his subjects and learn about their problems, His Majesty King Bhumibol Adulyadej found that drought had become more severe in certain areas of the country and rainfall was inconsistent.
Early in his reign, His Majesty the King became interested in artificial rainmaking to assist farmers, who are very dependent on rainwater for their cultivation. At this point, he began to study artificial rainmaking techniques to seek ways of bringing down more rain to ease the drought situation. He read research work on meteorology
In 1955, when His Majesty visited northeastern provinces, he traveled from Nakhon Phanom to Kalasin, passing through Sakon Nakhon and the Phuphan mountain range. During the trip, he looked at the sky and saw a large number of clouds moving over the vast, arid area of the Northeast. The initial conception arose from his observation that there was no rain despite heavy cloudiness. He wondered how to make the clouds move down and turn into rain. This idea was the starting point for his efforts to conduct rainmaking operations, which proved successful in the following years.
His Majesty gives constant advice on target, coverage, and area, with analysis of geographical features, area selection, and other factors, to improve the accuracy and efficiency of the operations. He explained the three steps of the rainmaking process in a simplified and figurative manner:
Agitation, using weather modification techniques to form rain clouds
Fattening, or impregnating the rain clouds through the sprinkling of chemicals to make the water droplets condense
Attacking, flying the plane into the impregnated clouds, to further modify the surroundings and speed up the process.
His Majesty the King in 1999 discovered a new technique to increase cloud density at both upper and lower levels simultaneously to increase the amount and extent of rainfall. The royal rainmaking team tried out the new technique and it proved to be a very efficient way of inducing rain. He named the new cloud-seeding technique "Super Sandwich." As a joke, he sent rainmaking staff at the Bureau of Royal Rainmaking and Agricultural Aviation a photo of two round sandwiches taken by him, saying "Here is the Super Sandwich." More new techniques are being discovered and introduced to the people involved. His Majesty's ingenuity for inventing the rainmaking technology has been widely recognized and has made Thailand the center of tropical rainmaking activities in this region. He has applied modern technology to existing resources to improve rainmaking potential. Non-toxic and environment-friendly chemicals, devised by His Majesty, are used to stimulate the air mass upwind of the target area to rise and form rain clouds.