Clear air turbulence will become more common because of climate change, a recently published study says.
‘The climate is changing—not just where we live at ground level, but also where we fly at 30,000–40,000 feet,’ study author Paul D. Williams of Reading University writes.
Climate modelling results predict the average amount of light turbulence in the atmosphere will increase by 59 per cent, with light-to-moderate turbulence increasing by 75 per cent, moderate by 94 per cent, moderate-to-severe by 127 per cent, and severe by 149 per cent.
The study, which will be published in Advances in Atmospheric Sciences in May 2017, looks at the probability distributions for a set of 21 clear-air turbulence diagnostics and finds they generally gain probability in their right-hand tails when the atmospheric carbon dioxide concentration is doubled from pre-industrial levels. This doubling is expected to occur by the middle of this century.
The study says mid latitude jet streams in both the Northern and Southern Hemispheres are expected to strengthen at aircraft cruising altitudes as the climate changes. Climate change, by strengthening the vertical wind shears at aircraft cruising altitudes within the jet streams, may be increasing the frequency and intensity of clear-air turbulence.
Light detection and ranging (LIDAR) ultra-violet laser systems could mitigate the effects of increased turbulence by warning pilots of clear-air turbulence up to 5–8 nm ahead, ‘potentially enough lead time to alert passengers and crew or even to attempt an evasive manoeuvre’.
Previous studies have found LIDAR systems to be not cost effective but Williams concludes ‘it is likely that the business case will improve in future, as LIDAR technology becomes less expensive and clear-air turbulence becomes more prevalent.’