Ash clouds cause flight chaos
01 June 2011
For the second time in a year, a volcanic eruption on Iceland has caused chaos across much of Europe. The problem has been caused by clouds of ash that have been thrown many kilometres into the air. For Icelanders living near the volcanoes, life has changed dramatically. A layer of brown ash covers the houses, roads and fields. However, the huge clouds have also travelled for thousands of kilometres across Europe, grounding many aircraft.
The first eruption began in March 2010, when the Eyjafjallajoekull volcano began ejecting clouds of steam and ash. Over the next few months, thousands of flights were cancelled as the tiny particles spread over Europe. After the eruption stopped, flights returned to normal. Then, on 21 May 2011, the Grímsvötn volcano began to throw ash high into the atmosphere. Fortunately, although this eruption was larger than the previous one, it died down quite quickly. By the end of May, flights were back to normal.
One of the main problems for airlines and governments during such eruptions is to ensure passenger safety. When aircraft fly through a volcanic cloud, ash particles enter the jet engines and can result in engine failure. The ash can also severely damage the outside of the aircraft. It is therefore essential to find a way to track the cloud’s movements and work out its thickness.
Fortunately, Earth orbiting satellites, such as ESA’s Envisat, are able to image the ash clouds. They can also detect gases such as sulphur dioxide that have been thrown high into the atmosphere, often reaching the altitudes of scheduled flights. The data are sent to Volcanic Ash Advisory Centres which assess the possible hazard to aviation and send out warnings.
