Beijing uses high-tech to prevent rain from dampening Olympic opening
28/7/2008 17:15
Beijing has mobilized all its science and engineering capability,
including satellite monitoring and cloud seeding, to prevent rain from spoiling
the extensively expected Olympic opening ceremony on Aug. 8 as historical data
indicate a 41 percent precipitation chance on that date.
The Beijing weather
engineering office, under the Beijing Municipal Meteorological Bureau, takes the
lead in the Olympic weather modification project.
The office doesn't bother
to change a lot. It is asked to prevent rain from falling during the three and
half hours -- from 8:08 p.m. to around 11:30 p.m. -- onto the Bird's Nest, the
open-air National Stadium which will accommodate the opening ceremony.
A
technology developed by American scientists, cloud seeding is achieved by
shooting shells or rockets containing silver iodide particles into clouds. The
icy particles freeze drops in the clouds, make the drops continue growing and
eventually fall out of the clouds.
The weather engineering office is weaving
a defensive web from adjacent provinces to the Beijing suburbs. Twenty-six
control stations have been deployed to fend off clouds or delay their
movement.
The office hires 32,000 people, and recruits light aircraft,
rockets and shells to spread silver iodide crystals or dry ice in clouds 50 km
upwind of Beijing. Result estimates can be reported from control stations to the
headquarters within 10 minutes.
One silver iodide shell costs up to 88 yuan
(US$12.75), one rocket is priced at 2,000 yuan (US$290), and one aircraft trip
spends much more. About 100 shells or four rockets are used in each single
action, according to experts.
The office claimed to have eliminated a cloud
by airborne spread of infusorial earth on its top on June 2, 2005, which was not
found documented in an academic journal.
Meteorologists need to capitalize on
radars and weather satellites to monitor colossal storms, which are usually
unpredictable, and set off early warnings for Olympic weather services.
One
main strategy of the meteorologists is to engineer weather in order to keep the
Olympics dry for at least the first three and half hours. Such research and
experiments have been conducted since 2001 when Beijing successfully bade for
the Olympic host.
Many meteorologists agree that cloud seeding technology is
only effective to small or mid-sized clouds and thus impossible to influence
giant storm systems, which can cover up to a hundred square kilometers. The
methodology is employed basically to speed up rain, delay rain, or change the
place where rain falls, one Beijing-based expert said.
Some meteorologists,
meanwhile, argue the study on cloud formation and large-scale weather conditions
is insufficient to effective weather modification. Others dispute on the
negative impact of spreading silver iodide in the sky on environment.
Yu
Xinwen, a China Meteorological Administration (CMA) spokesman, said in Beijing
today that the statistical probability of 41 percent, based on the
meteorological data collected in the past 33 years, just offers a rough idea on
a historical chance of precipitation.
An instant case is the 15th Asian Games
in December 2006 in Doha, Qatar. In a country where rain has been rarely seen, a
deluge soaked athletes and spectators during the expensive and breathtaking
opening ceremony.
However, Yu said, "It's possible to predict the weather at
the opening night one week in advance, and prediction accuracy will scale up
leading to Aug. 8." He expected more precise predictions within two days before
the Olympics.
As historical data indicate, early August is often warm and
humid, and might not be an ideal timing for the Olympic opening. Many thought
the Beijing Olympic organizers deliberately chose the auspicious eighth day of
the eighth month. However, organizers said it was not the
fact.
Fortune-conscious Chinese do care lucky numbers, among others 8 is the
best to represent prosperity and wealth. But decision makers were briefed by
meteorologists that the week beginning with August 8 usually falls in the
wettest period each year in Beijing.
It was reported that the Beijing
organizers proposed the International Olympic Committee (IOC) to kick off the
Games, ideally, on Aug. 15. The final decision of the Aug. 8 option from the IOC
left Beijing the only choice to prevent rain, at least around the sky of the
Bird's Nest.
The urgency on weather engineering for the Olympic opening is
based on one assumption that the main sports venue has no roof. Architects did
include a controlled full roof in their original design. The roofless version,
which now stands in north of the city, allegedly saved taxpayers 300 million
yuan (US$43 million).
Xinhua
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