Surfing the Jet Stream Reduces Aviation Radiation

Feb. 12, 2020: Something strange is happening in the North Atlantic. For the past three years, airplanes have been flying across the ocean in record time. Credit the jet stream. It’s revved up, possibly by climate change, and planes that surf it are flying faster than ever before. The latest record was set just days ago. On Feb. 8, 2020, British Airways Flight 112 (BA 112) rocketed from New York to London in a mere 4 hours 56 minutes, at one point traveling faster than 825 mph.

This is good news, because airplanes surfing the jet stream absorb significantly less cosmic radiation.

baw112

(Top) The flight path of British Airways 112 and (Bottom) The transatlantic jet stream on Feb. 8, 2020.  Credit: FlightRadar24.com

Researchers have long known that air travelers are exposed to cosmic rays. At typical cruising altitudes, passengers absorb 50 to 100 times more radiation than they would at sea level. This has led the International Commission on Radiological Protection (ICRP) to classify pilots and flight attendants as occupational radiation workers.

The jet stream can reduce this exposure. By propelling the passengers of BA 112 across the Atlantic at record speed, the jet stream lowered their radiation dose by about 30%. Two Virgin Atlantic flights following close behind the British Airways Boeing 747 experienced similar reductions.

These conclusions are based on E-RAD, a new model for aviation radiation. Since 2015, we (Spaceweather.com and the students of Earth to Sky Calculus) have been collecting X-ray, gamma-ray, and neutron radiation data onboard airplanes. Our database contains more than 25,000 radiation measurements over 27 countries, 5 continents, and 2 oceans. E-RAD uses these measurements to predict dose rates on flights anywhere in the world.

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British Airways flies from New York to London every day. We applied E-RAD to BA 112 on several dates, comparing dosages on Feb. 8th, when the plane surfed the jet stream, to nearby dates when it didn’t. Surfing the jet stream shaved almost 10 uSv (microSieverts) off the total radiation dose, a reduction equivalent to about 1 dental X-ray.

It’s not all good news, though. The jet stream can cause trouble. An active, fast-moving jet stream is often filled with turbulence, making flights miserable for buckled-in passengers. Planes dodging the rough air can actually increase their flight times, boosting cosmic ray exposure instead of reducing it.

Oh, and did you want to go home? Passengers returning to New York from London have to cross the Atlantic against the jet stream. Their flights will be slower, increasing exposure time. Indeed, we calculated the radiation exposure for British Airways flight 177 on Feb 8th, which flew in the opposite direction, from London to New York. Passengers onboard that aircraft received double the dosage: 34.4 uSv (London to New York) instead of the 17.7 uSv (New York to London) received by passengers on the BA 112 flight earlier in the day.

Climate change research suggests that all of these effects will intensify in the years ahead. A seminal study in 2016 found that changes in atmospheric dynamics would increase round-trip times between London and New York despite the quickening jet stream. Unless you fly to London and remain there, you’re going to absorb more and more “rads on a plane.”

End Notes:

(1) The radiation dosages mentioned in this story are not dangerous. Typically, they amount to 2 or 3 dental X-rays spread out over hours instead of the quick, intense pulse you receive in a dentist’s office. A single flight is not going to kill you. For frequent flyers and flight crews, however, repeated exposure adds up over time and may pose health risks that are still poorly understood.

(2) Transatlantic flights have been breaking records for the past three years. In Jan. 2018, a Norwegian passenger jet set a record when it went 779 mph during a trip from New York to London. In Feb. 2019, Virgin Atlantic went even faster: 801 mph from Los Angeles to London. Then, on Feb. 8, 2020, a British Airways Flight 112 shattered those records: 825 mph from New York to London.

(3) A key article on this topic is Transatlantic flight times and climate change. Environmental Research Letters, 2016; 11 (2): 024008 DOI: 10.1088/1748-9326/11/2/024008

According to the study, led by Dr Paul Williams, an atmospheric scientist at the University of Reading, “the average jet-stream winds along the flight route between London’s Heathrow airport and New York’s John F. Kennedy International airport are predicted to become 15% faster in winter, increasing from 77 to 89 km/hr (48 to 55 mph), with similar increases in the other seasons. As a result, London-bound flights will become twice as likely to take under 5h 20m, implying that record-breaking crossing times will occur with increasing frequency in future. On the other hand, New York-bound flights will become twice as likely to take over 7h 00m, suggesting that delayed arrivals will become increasingly common.”

 

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