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Beijing is preparing to manipulate the weather to ensure that it does not rain on its National Day parade on October 1.

Zhang Qiang, deputy director of the Beijing Weather Modification Office, told China Daily that "artificial rain reduction" measures were in place for the National Day celebration. President Hu Jintao will give a speech and the military will parade past Tian'anmen Square during the celebration.

Similar moves were taken during the Beijing Olympic Games last year. Meteorological workers fired over 1,100 rain dispersal rockets from 21 sites in the capital on the eve of the opening ceremony, which prevented a rain belt from moving toward the stadium.

"From weather records for the National Day in Beijing in the past three decades, we see a 30 percent chance of rainfall, mostly drizzle," Guo Hu, head of the Beijing meteorological bureau (BMB), told China Daily.

The weather modification office will only attempt to modify the weather if it forecasts rain in the days leading up to October 1.

Zhang said experience shows that artificial rain reduction can influence regional weather, like the successful experiences in dispersing rain clouds during the Olympic Games. But it cannot prevent large-scale weather trends.

He did not provide details on the rain reduction measures planned for the National Day parade, which will mark the 60th anniversary of the founding of the People's Republic of China.

Despite the weather modification success during the Games, experts have felt uncertain about technologically preventing rain.

Ye Qian, assistant president of the Chinese Academy of Meteorological Sciences, said yesterday that humans haven't found an effective way to change weather.

"Artificial rain reduction is like boiling water. If you want to stop the boiling, you must turn off the fire before it reaches the boiling point. But we just cannot find the point," Ye said.

The common way for artificial rain reduction is cloud seeding - dispersing substances like silver iodide into the air to alter the microphysical processes within the cloud. The chemical can cause temporary incapacitation or possible residual injury to humans and mammals if intensively exposed.

But the amount used in rain reduction is small, which causes no harm to the environment or humans, Ye said.

The United Nations Environment Program said on its website there are no expected environmental effects associated with cloud seeding, except some limited harm caused by the chemicals.

The bureau records show that the average temperature on October 1 ranges from 16 C to 23 C and the average wind speed is 2 m per second, which is suitable for outdoor celebrations.

（英语点津 许雅宁编辑）

About the broadcaster:

Nancy Matos is a foreign expert at China Daily Website. Born and raised in Vancouver, Canada, Nancy is a graduate of the Broadcast Journalism and Media program at the British Columbia Institute of Technology. Her journalism career in broadcast and print has taken her around the world from New York to Portugal and now Beijing. Nancy is happy to make the move