What is Turbulence?
Most people who fly have experienced turbulence: a sudden bump, a drop, or a side-to-side motion. For passengers and crew, turbulence is often described in practical terms: light chop, moderate turbulence, severe turbulence, or simply “rough air.”
While those descriptions are useful, they are also subjective. The same turbulent air can feel different depending on the aircraft, altitude, phase of flight, seat location, and even a person’s expectations. Aviation needs a more consistent way to describe turbulence—one that supports flight planning, operational decisions, safety reporting, product development, and research.
That is where a quantitative measure becomes important. A standard metric allows turbulence to be described not only by how it felt, but by how strong the atmospheric disturbance actually was.
How to Measure Turbulence
Aircraft fly through the atmosphere, and the atmosphere behaves like a fluid. When air moves smoothly, the aircraft experiences relatively steady airflow. When air motion becomes irregular, with rapidly changing gusts and swirling motions, the aircraft may experience turbulence.
From a physics perspective, turbulence is closely related to energy in the atmosphere. More specifically, it involves the transfer of energy from larger air motions into smaller, chaotic motions called eddies. These eddies eventually break down and dissipate as heat. The rate at which that turbulent energy dissipates provides a useful way to describe the intensity of the turbulence.
Over time, aviation and atmospheric science have evaluated several ways to measure turbulence. The challenge is that a useful metric must be objective, repeatable, and meaningful across different aircraft and operational environments. The industry has increasingly aligned around the eddy dissipation rate, commonly referred to as EDR, as a standard measure.
What is Eddy Dissipation Rate (EDR)
Eddy dissipation rate, or EDR, is a measure from atmospheric physics that describes how quickly turbulent energy is being dissipated in the atmosphere. In simple terms, EDR helps quantify the intensity of turbulent air.
A higher EDR value means turbulent energy is dissipating more rapidly, which corresponds to stronger turbulence. A lower EDR value indicates weaker turbulence. Because EDR describes the atmosphere itself, it is considered an aircraft-independent measure. The same air mass has the same EDR value regardless of which aircraft flies through it.
However, the way that turbulence feels or affects the aircraft can still vary by aircraft type. A smaller business jet may respond more noticeably to a given EDR value than a large widebody aircraft, because aircraft size, weight, wing loading, speed, and control systems all influence the ride response.
This distinction is important: EDR measures the turbulence in the atmosphere, while the aircraft response describes how that turbulence is experienced by a specific aircraft.
How to Relate EDR to Turbulence
For aviation users, the value of EDR is that it helps translate turbulence from a subjective experience into an objective measurement. Instead of relying only on pilot reports or passenger descriptions, EDR provides a consistent numerical basis for classifying turbulence intensity.
EDR values can be grouped into severity categories. The International Civil Aviation Organization has identified commonly used EDR ranges for turbulence severity:
| Turbulence Severity | EDR Range |
| Light | > 0.1 and < 0.2 |
| Moderate | ≥ 0.2 and < 0.45 |
| Severe | ≥ 0.45 and < 0.7 |
| Extreme | ≥ 0.7 |
These categories help connect the science of atmospheric turbulence with real-world aviation operations. For flight crews and dispatchers, EDR can support better awareness of where turbulence may be present and how intense it may be. For researchers, it provides a consistent metric for analysis and model validation. For commercial and operational teams, it offers a clearer way to communicate turbulence information across different aircraft, systems, and users.
In practical terms, EDR helps aviation move from qualitative descriptions such as “rough” or “moderate” toward a standardized, data-driven understanding of turbulence. It does not replace operational judgment, but it provides a stronger foundation for measuring, comparing, and communicating turbulence across the industry.
How Aireon uses ADS-B data to detect turbulence to enhance airspace safety
AireonINSIGHTS Turbulence is a global, real-time monitor of turbulence events around the world. By combining Aireon’s space-based ADS-B data with the National Center for Atmospheric Research (NCAR) turbulence algorithm, it turns the global fleet into a distributed network of turbulence sensors — providing consistent visibility into where turbulence occurs and how severe it is, including over oceanic and remote airspace.
What is the methodology behind AireonINSIGHTS Turbulence?
Data Collection
Aireon’s satellite network continuously collects global ADS-B messages from 7,000 to 11,000 active flights at any given moment.
Turbulence Algorithm
The turbulence algorithm was developed over years of research by the National Center for Atmospheric Research (NCAR), to calculate the eddy dissipation rate (EDR) value according to aircraft type (737, A330, A320, etc).
Data Processing
Every minute, ADS-B data for all active flights is processed through the NCAR turbulence algorithm, which calculates the peak Eddy Dissipation Rate (EDR) experienced during that minute.
Distribution
Each of these EDR reports are then distributed to end users to be integrated into products already used by airlines.
Click here to learn more about AireonINSIGHTS Turbulence.
