UC Boulder - Stratosphere Winds Far More Destructive To Ozone Than Thought

[hatrack]

A surprising new University of Colorado at Boulder study indicates winds circling high above the far Northern Hemisphere have a much greater impact on upper stratospheric ozone levels than scientists had thought. According to Associate Professor Cora Randall of CU-Boulder's Laboratory for Atmospheric and Space Physics, the winds allowed near-record amounts of ozone-destroying nitrogen oxide gases, collectively known as NOx, to descend some 30 miles to the top of Earth's stratosphere in March 2006.

Because NOx destroys ozone, which heats up the stratosphere by absorbing ultraviolet radiation, the naturally occurring gases could trigger atmospheric changes that could have unanticipated climate consequences, she said.

In February 2006, winds in the polar upper stratospheric vortex -- a massive winter low-pressure system that confines air over the Arctic region -- sped up to rival the strongest such winds on record, said Randall. The only time more NOx was observed in the upper stratosphere was in the winter of 2003-04, when huge solar storms bombarded the region with energetic particles, triggering up to a 60 percent reduction in ozone molecules, said Randall.

"We knew strong winds would lead to more NOx in the stratosphere if there were solar storms," said Randall, who also is associated with CU-Boulder's atmospheric and oceanic sciences department. "But seeing that much NOx come down into the stratosphere when the sun was essentially quiet was amazing." Randall is the chief author of a paper on the subject being published in the Sept. 27 online issue of Geophysical Research Letters, published by the American Geophysical Union. Researchers from the University of Waterloo in Ontario, Canada, and the University of Michigan also contributed to the study.

EDIT

http://www.eurekalert.org/pub_releases/2006-09/uoca-wti092806.php