By Crispian Balmer
BEIJING, Aug 5 (Reuters) - China boasts that its scientists
can make enough rain to fill the Yellow River but as the
Olympics draw near the question is whether they can also
prevent a deluge.
With forecasters predicting a 41 percent chance of rain on
the day of the Aug. 8 opening ceremony, officials have said
China was considering deploying experimental technology to try
to ensure dry weather and clean air for Friday.
However, many other nations have abandoned such
meteorological manipulation projects and state research has
largely dried up because of nebulous results.
"The most recent scientific assessment says there is very,
very slim evidence of the success of weather intervention in
increasing, decreasing or preventing rain," said Leonard
Barrie, co-director of the World Meteorological Organization
research department, based in Switzerland.
"In a way you can regard Beijing as a demonstration of
their weather modification capabilities," he told Reuters.
August is the rainy season in Beijing, with thunderstorms a
regular feature that could wreak havoc with the Games.
Organisers are especially anxious about the lavish opening
ceremony which will be played out in the national "Bird's Nest"
stadium in front of a TV audience to be numbered in the
"We will see if certain weather conditions will affect
Beijing and if we need to apply certain techniques," said Zhang
Qiang, deputy head of the Beijing Weather Modification Office.
There are two main methods of controlling rainfall.
Either the Chinese could try to induce rain before it
reaches the city centre, by firing a chemical agent into clouds
to "seed" them and make them more efficient at generating ice
crystals that melt to produce raindrops -- effectively draining
Otherwise they could use a coolant that increases the
number of water droplets in the cloud formations, thereby
decreasing their size and making them less likely to fall as
Cloud-busting technology has already been deployed at
previous sporting events, and with considerable success if one
believes the assertion of Russian scientists.
They have said their "cloud-seeding" activities kept the
rain at bay during the 1980 Moscow Olympics and again during
the fortnight of the Goodwill Games in 1994 in St. Petersburg.
But many scientists are sceptical about the real success of
manipulation programmes, saying it is very hard to assess how
much rain any seeding really provokes.
"Although the principles behind it are well established, it
is difficult to prove that a given round of cloud seeding
produced a particular effect," says the U.S. National Center
for Atmospheric Research based in Colorado.
Two years ago, China was bullish about its capabilities,
saying it had created the "world's leading force" in making
"Its aircraft alone have undertaken enough missions to fill
four Yellow Rivers, the country's second longest river, in the
past five years," the official Xinhua news agency said.
But the Chinese Weather Modification Office has itself
sought to play down its chances of success should bad weather
threaten to rain on its athletes' parade, suggesting it is
powerless to halt the progress of thick storm clouds laden with
"(Modification) of clouds and rain are only at the early
stages of experimentation," deputy director Zhang said.
(Additional reporting by Lucy Hornby)
(Editing by Ed Osmond)
(For more stories visit our multimedia website "Road to
Beijing" at http://www.reuters.com/news/sports/2008olympics;
and see our blog at http://blogs.reuters.com/china)