Forecasting method to help airplanes avoid air turbulence

Europe Sun (IANS) Thursday 2nd October, 2008

It hits aircrafts out of the blue, bouncing, trouncing and jolting them midair as if they were made of straw, an experience so unnerving that it causes tens of millions of dollars in injury claims every year.

When a plane flies through them, the sensation is like being in a small boat on a stormy sea. But where a boat's skipper can see rough sea, gravity waves in the air are usually invisible, and pilots often don't know they are present until they are flying right into them.

A new forecasting method developed by a University of Georgia (UG) researcher could help pilots chart new courses around these patches of rough but clear air -- called clear air turbulence (CAT) -- that can turn an otherwise unremarkable flight into frightening ones.

'Our new method allows superior forecasts for CAT beyond the tools that have been in use,' said John Knox, an assistant professor at UG's Franklin College of Arts and Sciences.

The new method predicts energy associated with gravity waves-phenomena in the atmosphere that look like ocean waves but which can occur in clear air. They can be created by air flow over mountains, frontal boundaries or other causes, according to an UG release.

'Commercial aircraft encounter severe-or-greater turbulence about 5,000 times each year, and the majority of these occur 10,000 feet above the earth's surface. This new method gives pilots a way to avoid turbulence that's not associated with nearby thunderstorms or significant cloudiness,' he said.

Other co-authors of the study include Donald McCann of McCann Aviation Weather Research, Overland Park and Paul Williams of the department of meteorology at the University of Reading in Great Britain.

These findings were published on Wednesday in the Journal of Atmospheric Science.