Types Of Turbulence

The natural phenomenon known as turbulence is a common safety risk to aircraft in flight around the world. It is defined as the change in the flow of air currents in a short distance. Having many different types, turbulence can be encountered in any phase of flight. Some of the most dangerous types of turbulence are wake vortex, mountain wave, and clear air. Each of these types have specific characteristics and conditions in which they occur. Wake vortex turbulence is produced by an aircraft generating lift. Wake vortices are produced when the high-pressure air under the aircraft wing flows to the low-pressure area on top of the wing by the shortest means possible at the wing tips. The pressure differential that causes this movement is greatest

As the name suggest, there are few visible signs for clear air turbulence. Thin cirrus clouds can form where wind velocity changes suddenly. Clear air turbulence occurs normally, in or around the jet stream. More specifically, flights flying at flight levels near the tropopause can experience clear air turbulence due to the temperature inversion occurring in that transition between the two spheres. Moreover, flights which cross a strong jet stream near mountainous terrain should anticipate clear air turbulence. This is because what was discussed earlier: mountain wave turbulence can reach up to 70,000 feet and 300 miles downwind of a mountain range. This combined with horizontal wind shear can lead to very rough air. The intensity of clear air turbulence can vary depending on many factors including but not limited to a high temperature gradient, high speed gradient, and the size of air masses. There are tools available to pilots to help plan and avoid turbulence. The winds aloft graphic allows pilots to choose altitudes and see the temperature and winds velocities at that altitude for the entire United States. This allows for pilots to visually see where wind velocity and temperature shift drastically. Furthermore, the Aviation Weather Center produces a turbulence forecast which uses the eddy dissipation rate to identify areas of turbulent air. A pilot should also check the Pilot and Aircraft reports for any known turbulence along their route of flight and plan around them if possible. However, when checking these, make sure to check the type of aircraft the reported it, as the turbulence may not affect your aircraft the same (i.e. a 747 experiences light turbulence, a C-172 may experience