Sunday, 17 April 2011

The fire next time

Last year’s volcanic-ash chaos in Europe is yielding lessons for the future
This is not an exercise

THE first anniversary of the eruption of Eyjafjallajokull, the volcano whose ash grounded most aircraft in Europe for days, was marked in a perfect way. On April 12th, almost a year later, a plume of ash rose 11 kilometres into the sky above Grimsvotn, another of Iceland’s regularly erupting volcanoes. Airlines and air-traffic controllers across Europe quickly took note. Transfixed by images of the ash cloud on a new visualisation system created for the purpose since Eyjafjallajokull’s eruption, they set up a “crisis cell” and sent out changes to flight plans.

These messages, though, were helpfully prefixed “Exercise Volcex 11/01 Exercise”. Grimsvotn’s eruption was a purely notional one, part of a two-day drill involving 70 or so airlines and other operators, a dozen air-traffic control systems and a variety of other bodies. In a similar exercise in 2008 only two airlines participated. But that was before last year’s 100,000 flight cancellations, airline losses put at over €1.3 billion (then $1.7 billion) and systemic knock-on effects on everyone from Kenyan farmers to Korean suppliers. Should another ash cloud rise to the skies, Europe will be better able to cope.

Last year’s standstill came because some regulators of Europe’s fragmented and highly congested airspace shut things down completely—mindful of advice that volcanic ash should always be avoided. One of the aims of Volcex 11/01 was to test a new approach to safety developed by the International Civil Aviation Organisation’s task force on volcanic ash, set up last July. It would do away with blanket bans in favour of a more targeted way of dealing with the risk. National regulators would make decisions based on assessments by aircraft operators that took in flight plans, equipment and the ash’s disposition.

Scientific preparedness is improving too. Britain’s Met Office, which is responsible for advisories on risks to aircraft from Icelandic ash, predicts the movement of ash clouds with a model built after the Chernobyl disaster. It takes a weather-forecasting model of the atmosphere and injects particles of a specified mass and size at a particular place (the “source term”). Then it sees where the weather takes the particles. Many think simulations of the spread of Eyjafjallajokull’s cloud put too much ash at the source. A new mobile radar stationed in Iceland should, says Ian Lisk of the Met Office, make the observations for the source term, now the largest source of error, more reliable. The Met Office also now has a “contingency aircraft” kitted out for ash studies that can gather data whenever it may be needed.

However good the source term, though, such models get further from reality as time goes on. Some cloud modellers are considering using the fact that ash, unlike fallout, can be seen from afar to make better calculations. Observations from ground, air and satellite of the ash’s extent at specific times might be used to create a series of model runs that would track it better. Yet satellite coverage doesn’t always allow for good snapshots; nor does the weather, which can put clouds in the way.

It is pleasing, if no more than proper, that Eyjafjallajokull should provoke new and even joined-up thinking from scientists, regulators and airlines. How much good this has done will be seen when Grimsvotn or another of Iceland’s 130 volcanoes next puts some of the world’s busiest airspace to the test—for real.