The first image shows the chaos inside the cabin of a Singapore Airlines flight experiencing severe turbulence, while the second image displays a damaged galley. Source: Nature website.
Recently, a Singapore Airlines flight en route from London's Heathrow Airport to Singapore's Changi Airport encountered severe turbulence, forcing an emergency landing at Bangkok's Suvarnabhumi Airport. The incident resulted in 2 fatalities and dozens of injuries. Data indicates a rapid descent of approximately 2133 meters within minutes, causing passengers and objects to be thrown towards the cabin ceiling. This marks the airline's first fatal accident in 24 years.
This rare event has raised questions about the nature of turbulence that caused such severe disruption to the flight. Could climate change lead to more frequent and stronger turbulence? What technologies exist to prevent severe turbulence? An article on the Nature magazine website highlighted that climate change may result in passengers encountering more unstable weather conditions during flights, increasing potential risks.
Professor Shen Haijun from Tongji University's School of Aerospace Engineering and Mechanics emphasized the importance of safety measures such as fastening seat belts for passengers to ensure flight safety.
Clear-air turbulence poses particular danger
In the history of aviation, human endeavors have often been challenged by air currents, with turbulence being a formidable opponent.
Shen Haijun explained, "Turbulence refers to irregular airflow caused by factors like the Earth's rotation, monsoons, jet streams, temperature differentials, terrain obstacles, and aircraft wake. Turbulence is generally categorized into mild, moderate, severe, and extreme."
Most flights experience some degree of turbulence. Strong winds around airports during takeoff or landing can create turbulence. In high altitudes, flying near or through storm clouds can lead to mild to severe turbulence caused by upward and downward air currents within the clouds.
Paul Williams, an atmospheric researcher at the University of Reading, mentioned that updrafts over mountains can also generate turbulence. When air flows over mountains, aircraft may experience lift and turbulence. Additionally, turbulence often occurs at the edges of jet streams.
It's worth noting that just as calm seas may hide strong undercurrents, clear skies can occasionally harbor intense disturbances in airflow, causing aircraft to experience severe turbulence. Meteorologists refer to this as "clear-air turbulence," which is particularly hazardous as its traces are challenging to detect with current technology.
Turbulence affects aircraft performance, structural loads, and flight safety. The National Weather Service in the U.S. stated that in extreme turbulence, aircraft can experience "violent shaking, nearly uncontrollable." Williams added that severe turbulence can turn individuals into projectiles, akin to riding a roller coaster without restraints for those not wearing seat belts.
Climate change impacts turbulence frequency
In a study published in the Geophysical Research Letters journal last year, Williams and colleagues found a significant increase in clear-air turbulence occurrences from 1979 to 2020. Over the North Atlantic, the frequency of severe or extreme clear-air turbulence rose by 55%. Similar increases were observed in turbulence frequency in other parts of the world. The research team attributed this growth almost certainly to climate change.
In another study published in the Geophysical Research Letters journal, Williams and colleagues used climate models to predict that as global warming continues, clear-air turbulence will become more severe and frequent. They estimated that severe turbulence occurrences will surpass those of mild or moderate turbulence.
Furthermore, another study suggested that with climate change, clear-air turbulence around clouds and mountains will become more frequent.
Williams noted that while turbulence may increase, most flights will continue to operate as usual. The increase in turbulence does not mean flights must be grounded or that aircraft will suddenly fall from the sky. The difference lies in potentially enduring 10 minutes of severe turbulence during a flight now, compared to possibly enduring 20 or 30 minutes in the future.
Can severe turbulence be predicted?
Professor Shen Haijun explained that technologies for predicting severe turbulence include meteorological data analysis, satellite imagery, ultra-high frequency and very high frequency radar, laser radar, and infrared long-range temperature sensors on aircraft.
According to Nature, meteorological center researchers predict turbulence based on data collected from ground sensors and satellites, which is then relayed to pilots. Onboard, pilots use radar to identify storm clouds and avoid potential turbulence.
However, Williams believes that conventional radar cannot detect clear-air turbulence that may occur in cloudless skies, suggesting that laser radar could assist pilots. Laser radar, similar to conventional radar but using different light wavelengths, has shown promise in experimental flights, being able to detect clear-air turbulence up to 20 miles away.
Williams highlighted that laser radar is costly and requires large, heavy equipment. He mentioned that if the size and cost of the equipment could be reduced, it might soon see wider usage.
Shen Haijun emphasized, "Technological advancements can safeguard passenger safety. However, from a passenger's perspective, always fasten your seat belt throughout the flight."
