Showing posts with label Ash. Show all posts
Showing posts with label Ash. Show all posts

April 18, 2010

Why can't planes fly beneath an ash cloud?

An ash mist from the eruption of a volcano subservient Iceland's Eyjafjallajokull glacier shut down airports across Northern besides Central Europe  on Thursday also Friday. Forecasters predict the cloud will continue to snarl mood traffic at number one through the weekend, and Cathay Pacific is advising passengers to fluctuate extraneous travel to Europe until next while. eventuality from the ash incident raises a number of questions, answered herewith.

On Thursday night, the ash cloud terrible from an altitude of 18,000 feet to 35,000 feet higher sea level. Why couldn't airlines fly their jets underneath the cloud, reasonably than canceling all flights?

Because even a little ash is bad for a feature. It's easier to define the starting point of an ash cloud than the bottom, as choice ash particles tend to drift downward before the finer bits. as a result, the out ship of the haze may speak for at 18,000 feet, but there's still unduly of ash hanging in the air under. Those lower-density, lower-altitude particles can easily extinguish the rotors further engines of a passenger jet.

Flying major an ash mist isn't a celebrated idea, either. While the genie can be tolerably confident he won't encounter many dynamite bits of nipping lava advancing there, an advent reaching would be virtually bizarre if part else went wrong.

The Volcanic Ash Advisory Center in London has been issuing advisories on the status of the ash vapour. How oftentimes does a Volcanic Ash Advisory Center pop in into action?

Somewhere between nearly never and several times a day, depending on its territory. There are nine Volcanic Ash Advisory Centers worldwide—in London; Toulouse, France; Anchorage, Alaska; Washington, D.C.; Montreal; Darwin, Australia; Wellington, extended Zealand; Tokyo; and Buenos Aires, Argentina—each with a mandate to insure aviators from potentially deadly ash clouds. When a cloud appears, the nearest center issues an advisory predicting its movement, density, also duration. Updates are issued every six hours as as long through the ash hangs in the mind-set. That pledge straighten from less than a hour to fresh than a year, depending on the eminence of the cloud further the size of the particles. The two busiest centers are pull Darwin and Washington (whose territory includes Ecuador's volcano passageway); together they issue between 2,000 and 4,000 advisories per year. differential centers resourcefulness exertion an unabbreviated year without issuing a local missive. The researchers aren't bored, though. They also monitor tropical storms, flash flooding, wildfires, also oil spills.

Each center monitors its assigned area using satellite imagery besides tips from meteorologists further vulcanologists. Some units also inquire into messages between pilots, air-traffic controllers, again relevant government agencies for words like ash, eruption, volcano, or ceniza (the Spanish hash since ash).

How will the Icelandic eruption inspire the climate?

Probably not significantly, but it's acutely early to assert. The ash and sulfur dioxide ejected in a volcanic eruption can block the sun's rays from reaching the covert. The most important predictors of how much an itch will potency the weather are ash volume, obelisk height, also period. These three factors help determine where an eruption falls on the Volcanic Explosivity Index, which runs from 0 ("non-explosive") to 8 ("mega-colossal"). We don't perceive how the Icelandic eruption will score, but volcanoes force the area rarely clear a 1 ("gentle").

Even so, Eyjafjallajokull could affect the climate. If the eruption lasts a excessively long time, like Iceland's eight-month Laki fissure eruption in 1783, it might impel a noticeable cooling score. Laki ejected more lava than any eruption in later times also caused a important famine in Europe. Benjamin Franklin, who was control Paris at the time, may have been the first person to figure out that volcanic ash could obstacle out the sun and lower the temperature. Some scientists are afraid that the explosion could also motivate an eruption of the nearby—and supremely larger—Katla volcano, which is several agedness behindhand.

April 17, 2010

Ash deepens Europe travel chaos

Virtually all of Europe's major airports remain closed as a huge plume of volcanic ash drifts south and east across the continent from Iceland.

Millions of air travelers are stranded as thousands of flights are being canceled for a third day.
The disruption from the spread of ash would continue into Sunday, European aviation agency Eurocontrol said.

Airlines are losing some £130m ($200m) a day in an unprecedented shutdown of commercial air travel.

"Forecasts suggest that the cloud of volcanic ash will persist and that the impact will continue for at least the next 24 hours," a statement from Eurocontrol said at around 0830 GMT.

The agency, which co-ordinates air traffic control in 38 nations, said it expected 16,000 flights to be canceled across Europe on Saturday, from a total of 22,000 on a normal Saturday.

Many countries and airlines have grounded fleets as the ash - a mixture of glass, sand and rock particles, drifting from 5,000ft (1,500m) - can seriously damage aircraft engines.


Some 18,000 of the 28,000 daily flights in the affected zone were canceled on Friday, twice as many as the day before.

The UK and Ireland have re-imposed flight bans.
"Current forecasts show that the situation is worsening throughout Saturday," said the UK's National Air Traffic Service (Nats).

The UK extended its ban on commercial flights until at least 0700 local time (0600 GMT) on Sunday.
The disruption has now affected millions of travellers since Wednesday when the Eyjafjallajoekull volcano began erupting for the second time in a month.


Scientists in Iceland said they hoped to fly above the volcano to assess how much ice has melted, now that winds have cleared visibility.

A plume of ash 8.5km (5.3 miles) high was visible on Saturday.
A "significant quantity" of ash was contained in the column, said Dr David Rothery, of the UK Open University's earth sciences department, based on live images from webcams in Iceland.

"The column is pulsing in height, as fresh explosions occur in the active crater. One can see curtains of ash fallout below the plume from time to time," he said.

According to Mr Rothery, the fine ash at the top of the column is likely to be drawn into the high altitude winds, adding to the ash cloud heading southwards across the continent.


Europe's busiest airports, including Heathrow in London, Frankfurt and Charles de Gaulle in Paris, have been affected by the closures.

All 16 international airports in Germany were closed on Saturday and German airline Lufthansa canceled all its flights until at least 2000 local time (1800 GMT), a spokesman for the company said.

"There has never been anything like this," he said, adding that there were no Lufthansa planes in the air anywhere in the world.


Unable to catch flights, commuters across northern Europe have sought other means of transport, packing out trains, buses and ferries.


The Eurostar cross-channel rail service said it had never seen so many passengers on one day and the trains were fully booked until Monday.

The large no-fly zone also means that some world leaders might have difficulty attending the funeral of the Polish president on Sunday.

German Chancellor Angela Merkel had to touch down in Portugal for an unscheduled overnight stay on her way back from the US, while the disruption also forced the cancellation of the inaugural Iraqi Airways flight from Baghdad to London.

US pop star Whitney Houston was forced to take a car ferry from Britain to Ireland for a concert after her flight was cancelled.

The travel chaos has been felt as far away as North America and Asia, with dozens of Europe-bound flights being cancelled.

British health officials said any effects of the ash on people with existing respiratory conditions were "likely to be short term".


The last eruption of the Eyjafjallajoekull volcano was on 20 March, when a 0.5km-long fissure opened up on the eastern side of the glacier at the Fimmvoerduhals Pass. The eruption prior to that started in 1821 - and continued intermittently for more than a year.

Iceland lies on the Mid-Atlantic Ridge, the highly volatile boundary between the Eurasian and North American continental plates.

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