Wake vortices
Organised forms of turbulence that are generated by aircraft, and can pose a severe hazard to following aircraft, particularly on take-off and landing. The movement and decay of wake vortices is a meteorological issue - we are working to identify and forecast the meteorological conditions that might contribute to the safe reduction of separations.

Volcanic ash
Volcanic ash clouds can severely disrupt flight patterns and damage aircraft in flight. The high risk of engine damage is of particular importance for the increasing number of twin-engine transatlantic flights. We are developing improved detection systems for ash cloud predictions, using satellite data along with an adaptation of the Met Office's proven atmospheric dispersion model NAME.

Clear air turbulence (CAT)
CAT is a significant problem for aircraft at cruising levels. Clear air turbulence is dangerous because it cannot be seen ahead: it occurs in the absence of clouds. There's a risk of aircraft damage but - more importantly - CAT can result in injuries to passengers and crew. In response to increasing demands for improved forecasts, we are investigating the two principal sources of CAT: 'shear' and 'mountain waves'.

Icing
Structural icing is a threat to safety and can lead to lengthy delays on the ground. Current contracts with the CAA and European Commission are looking at how often the combinations of liquid water content and drop-size distribution that cause aircraft difficulties occur.