Last week the AP reported on the government's plans to seed the clouds in Beijing to clear the air of dust:
Beijing was preparing on Tuesday to use artifical rain-making to clear the air after a choking dust storm coated China's capital in yellow grit, prompting a health warning to keep children indoors, state media said. The government was preparing to chemically seed the clouds in an effort to produce rain to clear away the air-borne dust, state TV said, citing the China Meterological Bureau. It didn't give any other details, and the bureau refused to release information.
This really goes on here. Late at night we hear loud BOOMS!, like a clap of thunder, but just one. Then, in the morning we'll notice evidence on the cars and ground that at least some precipitation came from the skies during the night--muddy splotches on the cars.
In September 1999, during the run-up to the huge celebrations marking the 50th ananiversary of the founding of the People's Republic of China, the president decreed that it must not rain on the parade scheduled to take place on Tiananmen Square on October 1. The night before, it was overcast, and rain was predicted for parade day. Early in the morning, before dawn, we heard loud BOOMS!, and sure enough, it rained, and got it out of its system before the parade started.
I can imagine a squadron of PLA soldiers who have been given the task if making rain for Beijing. They roam around the city in their jeeps, pulling thier artillery cannons behind them, gazing skyward in search of clouds. When they see one, the rush to within shooting distance, point their cannons at the clouds, and BOOM! A little while later, rain comes out of the cloud. Mission accomplished, they scurry off in search of the next cloud.
I don't like to think about what kind of chemicals they are using to produce the rain, but I suppose it doesn't really matter. Even when it rains naturally, it's acid rain, given the amount of pollution always in the air.
So, if you find yourself in Beijing sometime, and hear the mysterious BOOMS! at night, don't be surprised to wake up and see that it rained!