From the FECYT – Spanish Foundation for Science and Technology
Scientists ‘read’ the ash from the Icelandic volcano 2 years after its eruption
In May 2010, the ash cloud from the Icelandic volcano Eyjafjallajökull reached the Iberian Peninsula and brought airports to a halt all over Europe. At the time, scientists followed its paths using satellites, laser detectors, sun photometers and other instruments. Two years later they have now presented the results and models that will help to prevent the consequences of such natural phenomena.
The eruption of the Eyjafjallajökull in the south of Iceland began on the 20 March, 2010. On the 14 April it began to emit a cloud of ash that moved towards Northern and Central Europe, resulting in the closure of airspace. Hundreds of planes and millions of passengers were grounded.
After a period of calm, volcanic activity intensified once again on the 3 May. This time the winds transported the aerosols (a mixture of particles and gas) towards Spain and Portugal where some airports had to close between the 6 and 12 May. This was also a busy time for scientists who took advantage of the situation to monitor the phenomenon. Their work has now been published in the Atmospheric Environment journal.
“The huge economic impact of this event shows the need to describe with precision how a volcanic plume spreads through the atmosphere. It also highlighted the importance of characterising in detail its particles composition and establishing its concentration limits to ensure safe air navigation,” explains Arantxa Revuelta, researcher at the Spanish Research Centre for Energy, Environment and Technology (CIEMAT).
The team identified the volcanic ash cloud as it passed over Madrid thanks to LIDAR (Light Detection and Ranging), the most effective system for assessing aerosol concentration at a height. The CIEMAT station is one of 27 belonging to the European network EARLINET (European Aerosol Research Lidar Network) that use this instrument. Its members have also published a publicly accessible article on the matter in the Atmospheric Chemistry and Physics journal.
Using LIDAR technology, scientists direct a laser beam towards the sky, like a saber in Star Wars. The signal reflected back from particles provides information on their physical and chemical properties. A maximum aerosol value of 77 micrograms/m3 was estimated, which as a concentration is below the risk value established for air navigation (2 miligrams/m3).
Furthermore, the levels of particles rich in sulphates shot up even though they were fine particles (with a minimum diameter of 1 micra). This meant that they were much smaller than those particles over 20 micra found in countries in Central Europe.
These thicker particles are generally considered to be ‘ash’ and can really damage aircraft motors. The fine matter, like that detected over the Iberian Peninsula, is similar to that commonly found in urban and industrial areas. It is subject to study more for its damaging health effects rather than its impact on air navigation.
NASA’s network of sun photometers
It is important to track the evolution of all the particles in order to provide information to managers responsible for this kind of crisis. Working in this field were members of NASA’s AERONET (AErosol RObotic NETwork) network, which is made up by the different tracking stations in Spain and Portugal (integrated into RIMA) equipped with automatic sun photometers. These instruments focus towards the sun and collect data each hour on the aerosol optical thickness and their distribution by size in the atmospheric column.
The combined use of sun photometers and LIDAR technology boosts data collection. For example, the station in Granada and Évora revealed that the volcanic ash cloud circulated between 3 km and 6 km above the ground.
“Instruments like LIDAR are more powerful on an analytical level but their spatial and weather coverage is low. This means that sun photometers come in very useful in identifying volcanic aerosols when no other measures are available,” outlines the researcher Carlos Toledano from the University of Valladolid and member of the AERONET-RIMA network.
From their stations it was confirmed that “there is great variation between the size and characteristics of the volcanic aerosol particles over successive periods.” This was also verified by members of another European Network, EMEP (European Monitoring and Evaluation Program), which traces atmospheric pollution and is managed in Spain by the National Meteorological Agency. This group confirmed an increase in aerosols and their sulphate concentrations over the Iberian Peninsula and recorded the presence of sulphur dioxide from the Icelandic volcano.
Models and Predictions
The large part of observations of Eyjafjallajökull’s eruption, which were taken from aeroplanes, satellites or from earth, helped scientists validate their prediction and particle dispersion models.
“During the management of the crisis it became evident that there are still no precise models that provide real time data for delimiting an affected airspace, for example,” admits Toledano. Nevertheless, his team put the FLEXPART model to test using empirical data. From the Norwegian Institute for Air Research (NILU), it managed to calculate the arrival of volcanic ash in certain situations.
The powerful equipment available at the Barcelona Supercomputing Center (BSC-CNS) was used on this occasion to validate a model which had been developed at the centre: the Fall3d. As one of the authors Arnau Folch states, “the model can be applied to the dispersion of any type of particle. But, in practice, it has been especially designed for particles of volcanic origin, like ash.”
Volcanologists and metereologists use this model to re-enact past events and, above all, to make predictions. More specifically it predicts the amount of aerosols in the ground and their concentration in the air. It is therefore of “special interest” to civil aviation. The final objective is to make this type of prediction so as to be prepared during the next volcanic eruption.
References:
C. Toledano, Y. Bennouna, V. Cachorro, J.P. Ortiz de Galisteo, A. Stohl, K. Stebel, N.I. Kristiansen, F.J. Olmo, H. Lyamani, M.A. Obregón, V. Estellés, F. Wagner, J.M. Baldasano, Y. González-Castanedo, L. Clarisse, A.M. de Frutos: “Aerosol properties of the Eyjafjallajökull ash derived from sun photometer and satellite observations over the Iberian Peninsula”. M.A. Revuelta, M. Sastre, A.J. Fernández, L. Martín, R. García, F.J. Gómez-Moreno, B. Artíñano, M. Pujadas, F. Molero: “Characterization of the Eyjafjallajökull volcanic plume over the Iberian Peninsula by lidar remote sensing and ground-level data collection”. A. Folch, A. Costa, S. Basart: “Validation of the FALL3D ash dispersion model using observations of the 2010 Eyjafjallajökull volcanic ash clouds”. Atmospheric Environment 48: 22-32/46-55/165-183, March 2012.
M. Sicard, J. L. Guerrero-Rascado, F. Navas-Guzmán, J. Preißler, F. Molero, S. Tomáss, J. A. Bravo-Aranda, A. Comerón, F. Rocadenbosch, F. Wagner, M. Pujadas, L. Alados-Arboledas. “Monitoring of the Eyjafjallaj¨okull volcanic aerosol plume over the Iberian Peninsula by means of four EARLINET lidar stations”. Atmospheric Chemistry and Physics 12: 3115-3130, 2012. DOI:10.5194/acp-12-3115-2012.
Verity Jones says:
May 12, 2012 at 10:05 am
Interesting. I’ve been watching the earthquake maps at http://en.vedur.is/earthquakes-and-volcanism/earthquakes/myrdalsjokull/ for over a year. The activity there has been unremarkable enough lately to consider dropping it from my morning routine. However, the maps don’t show harmonic tremors, a sign of magma flowing in an open conduit.
Katla is home to the Mýrdalsjökull glacier the caldera is the ring displayed under the glacier. http://iceland.vefur.is/iceland_nature/volcanoes_in_iceland/katla.htm is a good overview of Katla.
The jonfr.com blog has a comment that leads to a graph of “Combined seismic and hydrological data” at http://hraun.vedur.is/ja/Katla/oroi/index.html . I think the red line is river flow, and that shows the spike mentioned in the blog. At least something is spiking.
BTW, one thing we haven’t touched on here is an eruption in the Canary Islands at El Hierro, see http://earthquake-report.com/2011/09/25/el-hierro-canary-islands-spain-volcanic-risk-alert-increased-to-yellow/ While activity has declined recently and alert levels dropped, for a while it looked like the undersea eruption would reach the surface.
Lucy Skywalker says:
May 12, 2012 at 1:56 pm
Seems to me it should be possible to fiter out the ash particles, with a removable filter for risky flights – rather than ground planes completely because they have no removable jet filters.
ferd berple and Dennis Cox nailed the explanation very well. A jet engine with a particle separator and ejection system would be heavy, noisy, horrendously inefficient, and too expensive to justify leaving in storage on the off-chance they’d be useful for a few hours of flying through a volcano’s plume some day.
The real show-stopper is that volcanic ash is both corrosive and abrasive — it eats aluminum, and airplanes are mostly aluminum. An aircraft that spent any time in the plume would have to be washed, the engines flushed, and then all components would have to be inspected.
It’s cheaper to either route flights around (or over) the plume or to cancel them for the duration.
ferd berple says:
Prez Carter’s Iranian hostage rescue failed because of the decision to use Marine helicopters instead of Army. This was a political decision, to “spread the glory” across the services. It resulted in a failure of the mission when a sandstorm was encountered en-route to Tehran.
Using technology similar to “never lose suction” vacuum cleaners, the Army units are fitted with vortex scrubbers to prevent catastrophic turbine failure when they ingest dust – which they do pretty regularly when landing on dirt. Before air enters the turbines, it is first spun in a vortex. The dust is forced to the outside of the air column, where it bypasses the turbine. The clean air from the center of the vortex goes into the turbine.
I can’t see how this could be applied to turbofan and turboprop engines.
Even fitting such a device to the APU wouldn’t help much since most aircraft have a RAT (or ADG) which deploys automatically in the case of loss of all generators/hydraulic pumps.
How much “bleed air” can an APU supply too?
Dennis Cox says:
May 12, 2012 at 4:20 pm
Since I was a UH-1 crewchief in the Army I can vouch for how well the scrubbers ferd berple describes work on a turboshaft engine in a helicopter.
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I learned this drinking beer with a retired helo pilot in a girly bar in Subic Bay a few years back.
There is an enormous dry-dock facility lying idle in the Philippines, in the Subic Bay economic zone. Slowly wasting away with age. While outside the gates are millions of young unemployed. Such a waste.
sabretoothed says:
May 12, 2012 at 5:33 pm
Is this why ozone hole appeared on northern pole right after?
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Perhaps it appeared at the north pole for the same reason it appeared at the south pole. It had always been there, just no-one had looked. The quantum mechanics wave collapse. Without an observer, it doesn’t happen.
Ric Werme says:
May 13, 2012 at 4:47 am
BTW, one thing we haven’t touched on here is an eruption in the Canary Islands at El Hierro, While activity has declined recently and alert levels dropped, for a while it looked like the undersea eruption would reach the surface.
Just so long as it doesn’t jolt that one-tenth-of-a-New-Jersey-sized rock loose from Cumbre Vieja. OT, but where are all the “Global Warming caused the eruption by melting the ice cap on the volcano and releasing the pressure” advocates that were swarming around here last time?
Marksays:
May 13, 2012 at 7:17 am
I can’t see how this could be applied to turbofan and turboprop engines.
Helicopter engines use “swirl tubes” ahead of the engine intake, which spins the airflow as it enters a plenum chamber. Centrifugal force flings the heavier particles onto the walls of the chamber — they slide down and are ejected through a vent. It doesn’t work with extremely fine dust (or ash) — we had to use barrier filters in Iraq. You could install a nested series of swirl tubes and plenum chambers on a jet engine, but the assembly would have to be as long as the engine itself and about three times the diameter in order to allow sufficient air to get to the engine. Not practical at all.
Even fitting such a device to the APU wouldn’t help much since most aircraft have a RAT (or ADG) which deploys automatically in the case of loss of all generators/hydraulic pumps.
You could fit a usable tube-and-plenum assembly onto an APU, but it wouldn’t do much — the APU only generates enough airflow to get the compressors spinning for engine start.
How much “bleed air” can an APU supply too?
A tap on the engine compressor section provides bleed air. As far as supplying forced air for engine starts, it all depends on the size and type of APU — some airliners have APUs the size of a UH-1’s engine.
Ref May 13, 2012 at 8:59 am: “…the APU only generates enough airflow to get the compressors spinning for engine start.”
There I go being Rooskie helicopter-centric. Some APUs are only used to generate electrical power to the starter and standby generators. Engine bleed air handles de-icing chores and “miscellaneous bleed air” tasks, such as cockpit and cabin pressurization,
Jet engines depend on cooling air passing through very fine geometry passages in the vanes on the turbine wheels in the hot section of the engine. Volcanic ash contains a great deal of very fine particles of low melting point glasses, which plug the cooling passages, and also gum up close tolerance clearances between rotors, stators an seals. Even if the engine doesn’t self destruct, many of it’s most expensive internals will be junk.
Mike Wryley says:
May 13, 2012 at 10:01 pm
Jet engines depend on cooling air passing through very fine geometry passages in the vanes on the turbine wheels in the hot section of the engine. Volcanic ash contains a great deal of very fine particles of low melting point glasses, which plug the cooling passages, and also gum up close tolerance clearances between rotors, stators an seals. Even if the engine doesn’t self destruct, many of it’s most expensive internals will be junk.
The molten glasses will also solidify when they hit the cooler portions of the engine interior, which is where the fuel nozzles are. Coat the ports in the nozzles with hot glass and you’ll have a flamed-out engine, and when all your engines are dead, your options are pretty much limited to making Mayday calls and waiting for the impact.
OK, this isn’t Icelandic, but it relates to we speakers of English having trouble with other languages. Enjoy!
http://en.vedur.is/earthquakes-and-volcanism/earthquakes/myrdalsjokull/ shows a cluster of quakes within Katla’s caldera about three hours ago, up to magnitude 2.2.
I think that http://hraun.vedur.is/ja/oroi/hvo.gif shows the recent harmonic tremor activity there.
Thank you for the update . . . Anthony this has been interesting . . . . especially because of the fact that the earth “spouts off” with alot of things . . . not just out of Volcanoes
As a sidebar I was re-reading the book an old book “The Fire Came By” about the 1908 Tanguska Event
http://en.wikipedia.org/wiki/Tunguska_event which the book theorized “alien spacecraft explosion”. . . .
http://www.amazon.com/The-Fire-Came-By-Explosion/dp/044689396X
After growing up and realizing the abundance of natural gas and how if forms naturally . . . I happen to postulate that it was a build up of natural gas that finally exploded . . . Given the history of Siberia’s sparse populations . . . It would explain why it was sparsly populated . . . (can’t breath methane and can’t smell it)
And the realization that if you have natural gas formations accumulating . . . you better use them or you lose them when they blow up with you and I along with it . . .
It’s also why GIGO can be so dangerous . . . .and why we must educate our populations (including non degreed people like me) as hydraulic fracturing seems to be the next phobia to come down the pike which will kill the natural gas industry leaving the hard work of many to the “easy pickings” of those that used to be “carpet baggers” . . . .
Have a good day . . . keep up the good work . . . Semper Fi
Laurie Bowen, there’s pseudoscience, science fiction, and then there’s real science. And the real science that’s been done at Tunguska has pretty much ruled out Alien spacecraft. And no methane explosion is ever going to produce a multi megaton airburst that makes Nagasaki, or Hiroshima look like a mouse breaking wind.
The real science that’s been done at Tunguska indicates it was the airburst of a hypervelocity object such as a small asteroid, or comet fragment.
please read: The Nature of Airbursts and their Contribution to the Impact Threat.
Semper Fi
Ok Dennix Cox I am slow . . . it says: “high-temperature jet of expanding gas” . . . . . I don’t mean to be hardheaded . . .but earthquakes build and we have large ones and small ones . . . . but on your side I guess there would have been massive burning . . . or are you saying there are not natural gas deposits there . . . so it is was an impossible event . .. .
The chemistry of the blast-effected materials at Tunguska has been studied to death. And the ET impact markers are well documented. Note that none of the real scientists who’ve been on the ground there, and have published peer reviewed literature about the place have ever thought it was jus’ plain ole swamp gas.
The event you describe is a physically impossible explosive event. There is no way that a methane explosion produced the magnitude of the blast effects, and the nature of the blast-effected materials found at Tunguska.
First of all to produce the blast effects we see there would require the detonation, and sudden burning of many many millions of tons of consentrated methane at very high altitude. And never mind the problem of where you’re going to get enough oxygen from to make it happen.
Simply put: SInce the burn rate of natural gas is so much slower than TNT, it is much less explosive. Even in the best of conditions you get something more like a very fast burning conflagration, than a detonation. So it is physically impossible to get enough concentrated methane, and oxygen in one place to produce an aerial explosion of methane that is equal to the detonation of 5 million tons of TNT.
Further Dennis Cox you got my curiosity . . . so I will add a couple more links for the possibility . . .
“””Our understanding was oversimplified,” says Boslough, “We no longer have to make the same simplifying assumptions, because present-day supercomputers allow us to do things with high resolution in 3-D. Everything gets clearer as you look at things with more refined tools.”
The new interpretation also accounts for the fact that winds were amplified above ridgelines where trees tended to be blown down, and that the forest at the time of the explosion, according to foresters, was not healthy. Thus previous scientific estimates had overstated the devastation caused by the asteroid, since topographic and ecologic factors contributing to the result had not been taken into account.
“There’s actually less devastation than previously thought,” says Boslough, but it was caused by a far smaller asteroid. Unfortunately, its not a complete wash in terms of the potential hazard, because there are more smaller asteroids than larger ones.
Boslough and colleagues achieved fame more than a decade ago by accurately predicting that that the fireball caused by the intersection of the comet Shoemaker-Levy 9 with Jupiter would be observable from Earth. “”
http://impact.arc.nasa.gov/news_detail.cfm?ID=179
Jupiter – Wikipedia, the free encyclopedia
en.wikipedia.org/wiki/JupiterCached – Similar
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Jump to Composition: Composition. Jupiter’s upper atmosphere is composed of about 88–92% hydrogen and 8–12% helium by percent volume or …
Laurie Bowen, I’m afraid I’m not very impressed with Wikipedia as a scientific reference. But If you’re interested in impact events, and since the focus of this blog is climate science, then a good blog that is focused on abrupt climate change induced by comets and asteroids during human history is George Howard’s The Cosmic Tusk.
As one of the original Authors of the 2007 paper in PNAS titled ‘Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling’ George isn’t into pseudoscience.
The cause, or trigger, for the Younger Dryas cooling, and the mega faunal extinctions 12,900 years ago, is still a very contentious issue in academia, and George maintains a complete and frequently updated library of good peer reviewed literature from both sides of the debate in the ‘Tusk’s document vault. Just look in the left column, and scroll down a little.