Photo: Doug (Flickr)
Flying through turbulence in an airplane is usually something of a nuisance; when that fasten-your-seatbelts sign comes on, you know you’re in for a bumpy ride.
On today’s Moment of Science, we’ll learn how airplanes use technology to avoid turbulence in the air ahead, and about systems that can help make flying a smoother, and safer, experience.
Much turbulence is “convective turbulence,” and it’s the result of air motion associated with storm clouds. To help detect and avoid convective turbulence, airliners use radar, which sends a radio signal ahead of the airplane.
If there are raindrops or ice in the air ahead, these radio signals bounce back, letting the pilot know where turbulence might be.
Using Radar To Determine Motion
A more sophisticated system uses the same radar to determine the motion of the rain and ice particles as well as their location. Turbulence is characterized by winds moving at different speeds.
If the airborne particles are moving in wildly different directions in one region, but moving in unison in another, the pilot will have a much better sense of exactly where the most severe turbulence is.
Clear Air Turbulence
Another system is needed to detect so-called “clear air” turbulence, or turbulence not associated with storm clouds. Researchers have developed a system that shoots an infrared laser beam ahead of the plane.
This works like the radar, bouncing off airborne particles and measuring their motion, but it is sensitive enough to measure the motion of tiny dust particles from miles away. Such particles exist even in the cleanest air, so this system would help detect any kind of turbulence, which might make flying a whole lot smoother.