Airborne turbulence is a well known nuisance for travelers, often bringing uncomfortable splashes and sudden jolts during flights. Recent findings indicate that these disturbances contribute to a substantial portion of in flight injuries and are typically mild in severity. With the climate warming trend, scientists anticipate a rise in both how often and how strong these turbulences will be in the coming years, underscoring the importance of safety measures on board. Seat belts should be fastened when advised, as a precautionary habit rather than a reaction to a single event.
Even though winter has traditionally shown the most turbulence, computer models project that by 2050 summers could experience turbulence intensities comparable to the winters of the past. The research behind these projections appears in the study titled Clear Air Turbulence Trends Over the North Atlantic in High Resolution Climate Models, published in Climate Dynamics.
Clear Air Turbulence CAT is one of the most harmful air related hazards. It tends to occur in cloudless regions of the upper atmosphere and often presents no visual cues to pilots. Onboard radar cannot detect it with certainty, and CAT can seem to appear without warning.
Prolonged exposure to this type of disturbance can shorten an aircrafts usable life and reduce mission time in service. Increased intensity can stress aircraft systems and, in extreme cases, lead to structural damage. Moderate turbulence can cause cargo, luggage and passengers to shift, resulting in damage or injury.
In December 1997 a Boeing 747 flight UA826 operated by United Airlines encountered a CAT event on a route from Tokyo to Hawaii. The aircraft experienced upward accelerations near 1.8 g, sideways acceleration near 0.1 g, followed by a rapid descent with negative gravity near -0.8 g. One passenger died and others were seriously injured. The incident prompted reassessment of flight operations and safety provisions.
Transatlantic travel frequently encounters CAT due to mid latitude jet streams that form over the North Atlantic. Researchers note that CAT events arise in unstable regions influenced by the shear in the atmosphere. These events commonly occur along high level jet streams in narrow wind bands and show a strong seasonal pattern.
14 percent rise per degree of warming
The strength of the jet stream responds to latitudinal and horizontal temperature differences. As pole to equator temperature changes occur, jet streams are expected to sharpen in the wind shear zones under human driven climate change.
To study this process, the researchers used three global climate models covering 1950 to 2050 and integrated them with 21 mechanisms for turbulent airflow to generate a broad set of CAT scenarios.
Findings indicate that for every 1 degree Celsius of near surface warming, moderate CAT events rise by 14 percent in summer and autumn and by 9 percent in winter and spring. Moderate turbulence is defined as vertical accelerations reaching up to 0.5 g.
Earlier work by Paul D. Williams of the University of Reading highlighted that if pre industrial CO2 levels doubled, CAT could increase by 40 to 170 percent in the North Atlantic, underscoring the sensitivity of these events to climate forcing.
As turbulence grows across seasons, existing flight plans may need adjustment. Airlines might consider routing around high CAT regions, a strategy that could lengthen some transatlantic journeys and add fuel costs. The implications for crew training, passenger safety, and aircraft maintenance are substantial and warrant ongoing attention.
…
The study points to the environment department as a general contact point for further information.