Organisers to give Olympic clouds a silver
lining
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Jonathan Watts in Beijing
The Guardian, Saturday 12 May 2007
Article history
Three defensive perimeters, dozens of cannon, hundreds of rockets and - on standby at a
nearby airport - a fleet of five planes laden with thousands of silver-iodine pellets.
No, it is not a new frontline in the war on terror. This is the cloudbusting arsenal that is being
put at the disposal of Beijing's weathermen as they fight to ensure blue skies for the 2008
Olympics.
Chinese metereologists are preparing one of mankind's greatest ever assaults on the heavens
next August, which the organisers belatedly acknowledge as the month when the capital gets
almost half its annual rainfall.
Two satellites have been launched to monitor the movements of threatening clouds. The
country's fastest supercomputer will crunch data while hundreds of meteorologists and
security personnel are being trained to shoot down cumulonimbus targets.
China is determined to master nature. Despite doubts about the effectiveness of the
technology and concerns about its effect on the environment, the government is preparing a
cloud-seeding operation on a massive scale. Cloud seeding, which started in the 1940s,
involves firing silver iodine or dry ice into a cloud where they act as a freezing nuclei. When
enough droplets thicken around them, they become heavy enough to fall as rain or snow.
The details were outlined in the China Daily which said the record of the past 30 years
suggests there is a 50% chance of rain spoiling the opening ceremony on August 8. Such
gloom is at odds with the sunny long-range forecast put out by the Games organisers, who
say the chance of inclement weather is 30% to 40%. "If it does rain, it will most likely be
drizzle," Jiang Xiaoyu, executive vice-president of the organizing committee, said last year.
For a city that has suffered drought for most of the last five years, August is an unusually
difficult month to predict. For the duration of the Games history suggests athletes will swelter
in temperatures of 25C with cooling downpours and thunderstorms every three or four days.
The meteorological bureau aims to establish perimeters at 15-20 km, 45-60 km and 90-120
km from the stadium. They are unlikely to work for large banks of clouds, but for smaller
formations scientists believe they can force 30% more precipitation than normal.
China claims more experience than most countries. Nationwide the cloudbusting army is said
to consist of 3,000 people, 7,000 cannon, almost 5,000 rocket launchers and jets that have
flown more than 3,000 missions.