Asian dust plume might sway U.S. climate: scientists

By Deborah Zabarenko, Environment Correspondent

WASHINGTON (Reuters) - Asian desert dust and city pollution is swirling in vast plumes across the Pacific to North America, interacting with storms and possibly spurring climate change, an airborne scientist said on Tuesday.

Jeff Stith of the National Center for Atmospheric Research communicated with reporters via Web chat from a research jet flying 40,000 feet above the ocean as part of a mission to track dust and pollution particles blown from Asia to the United States.

"We have found enhancements in pollution levels in some of the upper regions of the storm clouds we studied, just yesterday for example," Stith wrote.

Stith and his ground-based colleague, V. Ramanathan of the Scripps Institution of Oceanography, aimed to study the interaction between the pollution and dust with high-altitude clouds bearing ice crystals.

Ice crystals are found in extremely cold clouds, and when the crystals are composed entirely of frozen water, they reflect lots of sunlight -- that's why these clouds look so white, Ramanathan said by telephone after the Web chat.

However, if particles of dust and a dark pollutant known as black carbon managed to get inside the crystals, these clouds might absorb more solar energy rather than reflecting it all, Ramanathan said.

The high-flying jet, a specially equipped Gulfstream V, has a range of 6,000 miles and is needed to monitor the dust plumes, which speed across the ocean and occur every few days, the scientists said.

FAST-MOVING POLLUTION