Clear Air Turbulence (CAT) detection, Seeing the Unseen

I fly small planes and generally only if the skies are very clear. I’m constantly looking for traffic as well even if I have “flight following.” But anyone who’s been in a plane, big or small, has probably felt that uncomfortable feeling when the plane hits some turbulence. You can’t see turbulence in the air unless of course you’re flying through some nasty weather. In some cases turbulence can cause some serious problems to the aircraft itself, not just the passengers inside the plane. Seeing turbulence when there’s only clear skies ahead is not possible with our own eyes. Pilots might use “PIREPS” which are reports from other pilots to warn them about turbulence but there’s a company looking to detect clear air turbulence with technology that’s called LIDAR, or light detection and ranging instrument. This German agency is calling their system “DELICAT” (Demonstration of LIDAR based Clear Air Turbulence detection).

LIDAR sends out ultraviolet light. Guess what? If you read one of my other posts about the Tyndall Effect, the reason for the effect is because of short wavelength blue light bouncing off small particles (molecules). Ultraviolet light has an even shorter wavelength which we cannot see ourselves (there’s a trick to finding it though that I’ll show you). This ultraviolet light will bounce off small molecules in the atmosphere and can detect shifting patterns of clear air. Imagine that! We can detect molecules moving in clear air without even seeing this. Hopefully this will become a reality and be used on planes one day so we can don’t have to keep our seat belts on, as much!

I learned an interesting thing about cameras. Some of them can detect ultraviolet light. My old iPhone 4 doesn’t filter out UV light so it will detect the ultraviolet light from my tv remote. The front facing camera doesn’t seem to have a filter either on my ipad 3. You could try this with your own phone and a remote and see if yours can detect this as well. Check out the picture below of UV light coming from my tv remote.

TV remote with UV light on

TV remote with button pushed showing UV light

 

no buttons pushed

no buttons pushed