Global Courant
An airplane flying over Northamptonshire, England. For many, turbulence is an uncomfortable part of air travel.
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Turbulence during a flight can be an uncomfortable experience for many, ranging from mild bumpiness to more serious cases of damaged aircraft and injured passengers.
With millions of people heading off on summer holidays, a recent study by researchers in England provides some challenging, but important reading.
This is evident from the analysis published in Geophysical Survey Letters in June, turbulence in clear air (CAT) became increasingly common in certain parts of the world between 1979 and 2020.
Related to wind shear, turbulence in clear skies poses a specific challenge to pilots, as it is tricky to identify in advance and can appear without warning.
For example, the World Meteorological Organization say CAT “often — but not necessarily always — occurs in the absence of cloud cover, making it difficult to detect visually.”
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In a announcement in publishing the report, the University of Reading outlined some of the researchers’ key findings.
“At a typical point over the North Atlantic – one of the world’s busiest flight paths – the total annual duration of severe turbulence increased by 55% from 17.7 hours in 1979 to 27.4 hours in 2020,” it said. report.
In addition, moderate turbulence increased from 70.0 to 96.1 hours, while light turbulence reached 546.8 hours, an increase of 466.5 hours.
The university further stated that warmer air from carbon dioxide emissions “increases wind shear in the jet streams, amplifying turbulence in the North Atlantic and globally.”
The authors of the article say their research “represents the best evidence to date that CAT has increased over the past four decades, consistent with the expected effects of climate change.”
Airline passengers are required to fasten their seat belts when the sign is illuminated, and are advised to keep them on during the flight.
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Paul Williams, a professor of atmospheric sciences at the University of Reading and co-author of the study, spoke to CNBC and gave some context to the findings.
“(This) doesn’t necessarily mean that planes encounter turbulence, turbulence in clear skies, 55% more often, because of course planes try to avoid it and they’ve gotten very good at avoiding it,” he said.
However, there is “more turbulence in the atmosphere, period.”
“I think … it’s hard to believe that there could be 55% more turbulence in the atmosphere and that planes don’t have to deal with it more often,” Williams said. He also clarified that the report analyzed atmospheric observations rather than looking directly at aircraft measurements of turbulence.
The cost of turbulence
The consequences of severe turbulence vary.
Williams said they could include “internal damage to the aircraft from objects and people … collisions with the interior, usually the ceiling, and more mundane just routine wear and tear or what engineers call ‘fatigue’ of the aircraft.”
In a statement released last month, Mark Prosser, a PhD researcher at the University of Reading and co-author of the study, highlighted the financial implications of turbulence.
“Airlines will have to start thinking about how to deal with the increased turbulence as it costs the industry $150-500 million a year in the US alone,” he said, citing a figure on a website related to the NCAR Laboratory for Research Applications.
“Every extra minute spent traveling through turbulence increases aircraft wear and tear, as well as the risk of injury for passengers and flight attendants,” Prosser added.
How to manage it
So what can be done to reduce or control turbulence in clear air? Among other things, Williams emphasized the importance of improving forecasting.
“We need more research to understand exactly what causes turbulence and how to calculate it,” he said. “I think we need to invest in better turbulence forecasting research.”
When it comes to technology, there is room for significant developments in the coming years, even if challenges remain.
“While the radar in the cockpit can’t clearly see air turbulence, there’s a related technology called LIDAR that stands for light detection and range,” Williams said.
LIDAR, Williams explained, works on the same principles as radar, but uses ultraviolet light and lasers instead.
“By using that other wavelength of light, we can see invisible, clear air turbulence ahead of us,” he said.
“They’ve done test flights and it works about … up to 20 miles in front of the plane … (so) you can see it on the screen in the cockpit and put on the seatbelt sign and try to fly around it.”
However, there is one big catch. “Unfortunately it’s very expensive and also comes in a big, heavy box, which you don’t really want to put on an airplane to add weight to the plane,” said Williams.
Although it is currently not used, things may change.
“In the future, if it’s likely to be miniaturized and costs come down and there’s also more turbulence in the atmosphere, we may see planes equipped with LIDAR later on. And that would be a game changer if it happens,” Williams said.
‘Hold on your seatbelt’
Will the problem of turbulence get worse?
“It certainly depends on our emissions,” Williams said. “Every extra degree Celsius of warming implies an extra amount of turbulence,” he added.
“To that extent, it’s in our control … (because) we can control the warming of our emissions. But, you know, I think … unless we do something drastic, there’s more turbulence in the coming decades.”
Williams also had some measured words of comfort for fliers who might be worried about such a prospect.
“I’m not suggesting that it’s going to get so bad that planes fall out of the sky or that we have to stop flying in certain parts of the world,” he said.
Severe turbulence, he added, is “quite rare – only 0.1% of the atmosphere at 12,000 feet contains severe turbulence, so if you’re on a plane it’s very unlikely your plane will hit that 0.1% .”
“However, given the number of planes in the sky, one of them will. But even if the turbulence tripled, it would still only be 0.3% of the atmosphere.”
His advice to passengers is clear. “I don’t think there’s a major concern for passengers here.”
“Obviously, it’s wise to keep your seatbelt on, just in case you’re unlucky and you hit that small part of the atmosphere that the turbulence is in.”
