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Air pollution affects storms
06/03/2007 10:39 - (SA)
Washington - Pollution from Asia is helping generate stronger storms over the North Pacific Ocean, according to new research.
Changes in the North Pacific storm track could have an impact on weather across the Northern Hemisphere.
Satellite measurements have shown an increase in recent decades of tiny particles generated from the burning of coal in China and India, researchers report in Tuesday's issue of Proceedings of the National Academy of Sciences.
The team, led by Renyi Zhang of Texas A&M University, studied pollution and clouds between 1984 and 2005 and concluded that the increasing particles enhanced the cloud updraft to generate more intense thunderstorms than previously.
Comparing 1984-1994 with 1994-2005 they found an increase of 20% to 50% in deep convective clouds.
The Pacific storm track, they noted, plays a critical role in global atmospheric circulation, and altering this weather pattern could have a significant impact on the climate.
"The intensified storms over the Pacific in winter are climatically significant," the researchers wrote. "The intensified Pacific storm track can also impact the global general circulation."
A particular threat, they added, is the potential for increased warming of polar regions.
The research was supported by National Science Foundation, Department of Energy and the National Aeronautics and Space Administration.
Montreal Protocol
In another report in the same issue of PNAS, researchers said that in addition to protecting the ozone layer, the reduction on ozone-depleting chemicals has slowed the rate of global warming.
The Montreal Protocol, signed in 1987, led to a reduction in chemicals released into the atmosphere in an effort to preserve the ozone layer that screens out many of the sun's damaging rays.
Those same chemicals are potent contributors to greenhouse warming, and their reduction has resulted in a slowdown in global warming, according to a team led by Guus JM Velders of the Netherlands Environmental Assessment Agency.
The savings in trapped heat are equivalent to about 10 years of growth in carbon dioxide concentrations, they estimated.
Joining Velders in that study were researchers from the US Environmental Protection Agency, the US National Oceanic and Atmospheric Administration and DuPont Fluoroproducts.
On the net:
www.pnas.org
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