Aviation turbulence in a warmer world

Clear-air turbulence is a major meteorological hazard to the aviation sector. Research by previous Scenario PhD students has revealed that severe clear-air turbulence has increased substantially around the world since satellites started observing the atmosphere in 1979. For example, there has been a 55% increase over the North Atlantic. These increases are projected to continue into the future, with a doubling or trebling expected by the period 2050-2080.

The increase in turbulence has consequences for aircraft design. The lifecycle of aircraft models is such that the aircraft that will be flying in 2050-2080 are currently in the design stage. Aircraft manufacturers (such as project co-sponsor Airbus) require that future aircraft can withstand the more turbulent atmosphere they will be flying through.

However, aircraft are currently designed and certified using a gust excitation intensity model derived from atmospheric turbulence measurements made in the 1960s and 1970s. Due to climate change, the gust perturbations are intensifying, but the impacts of the turbulence increase from climate change on the gust model have not previously been investigated.

This project will combine aircraft gust data from Airbus with atmospheric models to build an updated gust event statistics model that captures atmospheric behaviour today and how it will change in the future. The new model will be used by aircraft designers and manufacturers to protect future aircraft design and improve aircraft fatigue maintenance. It could also be used by aviation safety regulators to modify aircraft certification envelopes.

The atmospheric gust model currently used by the aviation sector to design aircraft has not been updated since the 1970s. This is despite plentiful evidence that atmospheric turbulence has been increasing because of climate change since the 1970s and will continue to increase in future. The student will update this gust model for the first time in five decades, making it fit for the more turbulent flying environment of the future.

The key challenge is to take atmospheric turbulence projections, which are traditionally quantified in terms of the turbulence eddy dissipation rate (which is the aircraft-independent turbulence measure that has been endorsed by the International Civil Aviation Organization) and embed them into the gust spectrum model (which for historical reasons is the turbulence measure that is actually used by aircraft designers and manufacturers). The updated gust model will allow Airbus to adapt the design of future aircraft in accordance with climate change, supporting Airbus's goal to achieve safe and efficient aviation in a changing climate.

It could also lead to regulatory changes to aircraft certification rules, as the European Union Aviation Safety Agency (EASA) is currently investigating how climate change could impact these rules.