Ten new Light Detection and Ranging Systems (Lidars) are set to be installed across the UK to improve the detection and aid forecasting of volcanic ash. The instruments will help minimise the kind of disruption and safety issues that followed the 2010 Eyjafjallajökull volcanic eruption in Iceland, which affected hundreds of thousands of passengers across the globe.
Volcanic ash consists of fragments of pulverised rock, minerals and volcanic glass, which can be spewed tens of thousands of feet into the air, reaching jet cruising altitude. The ash can have disastrous effects on jet engines, leading to many flights being cancelled following volcanic eruptions.
The network of ten Lidars designed to sense atmospheric particles around the UK, is part of a £3 million project funded by the UK’s Department for Transport.
Designed by Raymetrics, a manufacturer of backscatter, Raman and depolarisation Lidars for atmospheric analysis, the instruments send observations to the UK's Volcanic Ash Advisory Centre (VAAC), to provide more detailed information on the location and characteristics of ash that could impact aircraft flight paths.
This information will support improved forecasts on the dispersion of ash in order to ensure the safety of travellers and minimise any potential disruption, such as that caused by the Eyjafjallajökull volcano in 2010. The ash from its eruption led to the one of the largest air-traffic shut-downs in history.
‘The 2010 volcanic ash cloud led to flights being grounded for days at a time, not just here in the UK but across Europe and further afield, with knock on effects on international airports around the globe. It had a significant impact on travellers, the aviation industry, and wider economy,’ explained aviation minister Robert Goodwill.
‘This new equipment… will allow the UK's Met Office to track ash clouds more easily and predict how they might spread more accurately. That could play a big part in minimising disruption to flights during any future incident,’ Goodwill continued.
The Lidar devices probe the atmosphere using light from a pulsed laser source. Backscattered light from suspended aerosols is collected using a receiver (telescope) and analysed.
The information obtained through this method helps agencies to build up a profile of the vertical distribution and characteristics of particles in the atmosphere. Each unit will be collocated with a sun photometer to support ongoing research into more accurate and timely estimates of particle concentration levels.
Used in conjunction with data from satellites and other ash detection capabilities such as the Met Office Civil Contingency Aircraft (MOCCA), the information will provide experts at the Met Office with the best possible picture of real-time ash distribution.
During the 2010 volcanic ash incident, a network of older laser-based equipment, originally set up to measure cloud heights, was reconfigured to provide ash observations. The new LiDAR network will be more advanced and will include the capability to distinguish ash from other types of suspended aerosols.
The project is currently under way and is expected to be completed and operational by the spring of 2016.
Up in the air: Lidar remote sensing, used in various aspects of atmospheric research, provided crucial data for monitoring the ash cloud, as Greg Blackman finds out
Something in the air: Jessica Rowbury looks at the various light-based techniques for monitoring atmospheric pollution