Our Q&A blog series answers common questions about aviation and Southwest Airlines. Our first question about Turbulence is answered by Southwest’s Chief Meteorologist Rick Curtis. Have a question of your own? Leave us a comment!Most airplane flights experience some form of turbulence between takeoff and touchdown, but luckily most of the time it’s either very light or simply an irritation for a few seconds or minutes. Despite advances in technology and forecasting techniques avoiding turbulence is still very difficult. Think about it for a second—when we are on a boat or ship in the ocean we can easily see the waves ahead of us. The wave’s interaction and impact will greatly depend on the size of our boat. Since the atmosphere is also a fluid (like the ocean) the same holds true with airplanes. Turbulence that has a large impact on small airplanes may only provide a gentle “bump” to a commercial airliner.
When an airplane travels through the sky, the air around that plane is also moving. Air surrounding the aircraft can not only be moving towards or away the airplane, but also be rising or sinking. The same is true with ocean currents in our boat example. However, while airplanes have radar detection instruments, which help Pilots “see” turbulence, identifying turbulent air versus water is much more difficult.
There are a few basic types of turbulence and each has a different source; however, their effects on the comfort of your flight can be the same. One of the most common types of turbulence is found around thunderstorms. Airplanes obviously avoid and fly around thunderstorms; however, updrafts, downdrafts, and outflows from thunderstorms can have a turbulence impact on airplanes many miles away from a storm. Another common type of turbulence is experienced when flying over mountainous terrain. When the surface winds interact with mountains, the winds cause many fluctuations in the atmosphere and can “bounce around” thousands of feet about the mountain tops.
Another type of turbulence is often experienced is due to “thermals,” or rising air from the surface. As the sun warms the air at the surface it becomes lighter and begins to rise. This rising of air then becomes an “updraft,” which will impact an airplane in the form of turbulence when encountered.
Lastly, clear air turbulence is one of the toughest types to predict. Clear air turbulence is usually caused by wind shear in the atmosphere. Wind shear is the difference in wind speed or direction over a horizontal or vertical distance. As you can imagine detecting clear air turbulence can be difficult as we do not have the observing network in the air that we have on the surface.
Turbulence, although very common, is still one of the more difficult forecasts for a meteorologist to make. Our forecast models and observations are always trying to move to high resolution information, but we a still a very long way from being able to fully “see” and prediction turbulence on a very localized scale.
More and more commercial airplanes are beginning to automatically report turbulence (at last check, Southwest was up to 127 reporting aircraft). These additional reports greatly assist with the detection and forecast of turbulence. Over time, Southwest will be expanding our automated turbulence reporting capacity, which will greatly help forecasters identify and predict turbulence.
So the next time you are flying and feel those “bumps,” know they can be caused by a variety and combination of many different variables. Many efforts are taking place “behind the scenes” and within the flight deck to minimize the encounter of turbulence on your flight as much as possible.
Photo by BWI Flight Attendant Michael Demouy