Turbulence

Turbulence is a meteorological phenomenon caused by the irregular, sudden, and unpredictable movement of air currents in the atmosphere. In aviation terminology it is also referred to as atmospheric turbulence. Turbulence occurs when air masses undergo abrupt changes in direction and speed, creating complex motions in vertical or horizontal planes. These movements can disrupt aircraft stability during flight, leading to shaking, sudden altitude changes, or control difficulties.

Turbulence Map dated 21 October 2025 (Turbulence Forecast)

Turbulence is considered a significant risk factor in international aviation due to its potential to cause structural damage and threaten passenger and crew safety. In particular, types of turbulence occurring under clear sky conditions cannot be detected by radar systems, making them especially unpredictable.

Levels of Turbulence Intensity

In international aviation literature (AIM – Aeronautical Information Manual) and in the study by Klimenko & Krozel (2009)^【1】, turbulence is classified into four primary intensity categories based on its effects on the aircraft and cabin.

^{Table on Turbulence Intensity and Effects (Aeronautical Information Manual)}

Types of Turbulence by Source

There are four main types of atmospheric turbulence, classified according to their origin.

Clear Air Turbulence (CAT)

CAT occurs at altitudes between 6,000 and 15,000 meters in cloud-free regions, particularly along jet streams. The primary cause is sharp wind shear between air masses. According to AIAA research, CAT forms in areas where there are large differences in wind direction and speed at jet stream boundaries and cannot be detected by radar.

Convective-Induced Turbulence (CIT)

CIT arises from vertical motions caused by rising warm air currents due to uneven surface heating. It is commonly associated with cumulonimbus clouds and thunderstorms; it can be detected by radar reflections but does not always occur with precipitation.

Mountain Wave Turbulence (MWT)

These are oscillatory motions created when air flows rapidly over mountain ranges. These waves can rise above 20,000 feet (approximately 6,000 meters) and extend hundreds of kilometers downstream. MWT typically generates turbulence of “Moderate and Above” intensity.

Wake Turbulence

These are vortex motions left behind by aircraft wings as a result of lift generation. They pose a hazard to aircraft flying in sequence during takeoff and landing phases. ICAO has established minimum separation distances between aircraft to mitigate the effects of this turbulence.

Climate Change and Increased Turbulence

Modern atmospheric research shows that global warming is intensifying wind shear at high altitudes. According to Professor Paul Williams from the University of Reading’s analysis of data from 1979 to 2020, severe clear air turbulence over the North Atlantic has increased by 55%. This increase is attributed to changes in wind speed driven by temperature differences within jet streams. Consequently, future projections indicate that both the frequency and intensity of clear air turbulence will continue to rise.