RICHLAND, Wash., March 29 (UPI) -- Precipitation has been trending downward across most of the mountain ranges in central and eastern China, and many researchers believe pollution is to blame.
Hard evidence of this link has been lacking, though new research out of the Energy Department's Pacific Northwest National Laboratory is changing that.
Combining data collection and computer modeling, scientists at the national laboratory were able to show that air pollution is slowing valley breezes and diminishing surface moisture in the air surrounding Mount Hua, a peak in China's Shaanxi Province.
"As a result, the usual transport of water vapor from the valley to the mountain is significantly reduced," lead researcher Jiwen Fan, a PNNL atmospheric scientist, said in a news release. "This causes cascading effects that suppress convection -- the process that forms stormy rain clouds -- and precipitation over the mountain."
The pollution's wind- and moisture-negating interaction with sunlight energy is responsible for a 40 percent reduction of precipitation.
Smog problems in China's major cities has attracted the most media coverage and the attention of government policymakers, but downwind effects of aerosols and particulates may be equally worrisome.
Precipitation in China's mountains feed the rivers and reservoirs that millions of people rely on for drinking and farming.
Researchers published their findings in the Journal of the Atmospheric Sciences.