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.
Two years later they have now presented the results and models that will help to prevent the consequences of such natural phenomena.
The consequences (closing airspace or re-routing scheduled flights to avoid the thickest part of the plume) will still be contingent on someone taking an aircraft up into the fringes and collecting samples. Everyone in ICAO is still smarting from the overreactions produced by putting too much faith in what the models projected the last time [cut/paste] Eyjafjallajökull popped…
It’s hard to find a good pronunciation key. But this is close: Eye-ya-fi-yetla-yökull
Say it a bunch of times ’til you can comfortably run all those sounds together in one smoothly pronounced word without tripping over your tongue and you’ve got it.
I was with wife on an Easter break in Malta, it lasted 11 instead of 7 days due to our flight cancellation. Chaos around Europe was everywhere. I suggested to some of the friends and hotel guests (one PhD from a UK university) that temperatures in the following few months may rise slightly and then suffer a considerable fall (compared to previous average. It is difficult to prove one way or the other but the CET did show strong decline during following year:
http://www.vukcevic.talktalk.net/CET1690-1960.htm
The AGW advocates should take a good look at the graph for unrelated reason of comparing to the distant but unexpectedly similar ‘no industrial CO2 past’.
“Using LIDAR technology, scientists direct a laser beam towards the sky, like a saber in Star Wars.”
Science!
… Although if someone does make a scientifically useful handheld LIDAR unit, I’ll be suitably impressed by their engineering skills.
I got the “yokel” part a few years ago, during the first eruption. More work needed.
Not difficult to pronounce 🙂
Listen: http://www.youtube.com/watch?v=tEEXY6HrQ6Y
Regards from Iceland, Ágúst
Getting our act together just in time for the next one. Jón Frímann at the Iceland volcano and earthquake blog reckons Katla is warming up: http://www.jonfr.com/volcano/?p=2535
The Met Office are making sure they have real data too (so they won’t just rely on models 😉 http://www.metoffice.gov.uk/aviation/volcanic-ash-development-activities
“Aircraft-based Observations – The Met Office has placed a contract with Cranfield Aerospace and DO Systems for the provision of the Met Office ‘Civil Contingency’ aircraft. This twin piston engine Cessna aircraft is being equipped with a range of specialist instrumentation to measure the concentration of volcanic ash and to remotely sense the ash with lidar. The aircraft is currently being modified and will become operational in April 2011.”
Hey AnthonyMoose,
They’re already out there. Although I don’t know if they’d be much use to scientists. But one of these days when you get a speeding ticket from a sneaky cop who’s using a handheld laser unit that your expensive and cute little dash mounted Radar detector missed because he’s shootin’ folks in the butt with a tight laser beam after they pass by, you can be suitably impressed by someone’s engineering skills when you pay the ticket.
“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
Not according to the UK Met Off at that time. They were utterly convinced that their model was absolutely correct and it was on that model output that european air space was closed. Oh, but then again, we no just how good the UK Met off models are from experience 😉
I once heard someone try to pronounce it and my southwest-US-ears heard “Amber Lager”. Now whenever I see one of these articles I get thirsty.
a-ya-flat-la-yo-co-dl
As the only regular here on record as being able to pronounce both “Eyjafjallajökull” and “Popocatepetl,”
let me observe that I’ve heard so many people mispronounce “often” and “aunt” and “either” that I shouldn’t be surprised.
After watching several YouTube videos this seems to be the consensus pronounciation:
ei-ya–f’yet-la–yoer’-cu-dl’ (Eyjafjallajökull)
greems-v’kh (Grimsvotn)
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.
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.
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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.
Lucy Skywalker says: “Seems to me it should be possible to fiter out the ash particles, with a removable filter for risky flights…”
Nope. A filter material fine enough to stop these tiny particles will choke the jet engine.
I just call it “that volcano in Iceland.” Everybody knows what I mean. If another goes off, I’ll call it “that other volcano in Iceland.”
Tim C has posted a very interesting UHI study on my site of Heathrow Airport covering the period the volcanic ash cloud grounded flights.
http://tallbloke.wordpress.com/2012/05/12/uhi-at-heathrow-met-office-site-3/
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. But a turboshaft engine doesn’t have to produce any jet thrust. It only needs to spin a power producing turbine. And I don’t see how you could build something like that for a thrust producing jet engine like a large airliner uses that wouldn’t restrict way too much of the airflow through the engine.
Just an FYI from:
http://www.faa.gov/air_traffic/publications/atpubs/aim/aim0705.html
b. Most important is to avoid any encounter with volcanic ash. The ash plume may not be visible, especially in instrument conditions or at night; and even if visible, it is difficult to distinguish visually between an ash cloud and an ordinary weather cloud. Volcanic ash clouds are not displayed on airborne or ATC radar. The pilot must rely on reports from air traffic controllers and other pilots to determine the location of the ash cloud and use that information to remain well clear of the area. Every attempt should be made to remain on the upwind side of the volcano.
c. It is recommended that pilots encountering an ash cloud should immediately reduce thrust to idle (altitude permitting), and reverse course in order to escape from the cloud. Ash clouds may extend for hundreds of miles and pilots should not attempt to fly through or climb out of the cloud. In addition, the following procedures are recommended:
1. Disengage the autothrottle if engaged. This will prevent the autothrottle from increasing engine thrust;
2. Turn on continuous ignition;
3. Turn on all accessory airbleeds including all air conditioning packs, nacelles, and wing anti‐ice. This will provide an additional engine stall margin by reducing engine pressure.
d. The following has been reported by flightcrews who have experienced encounters with volcanic dust clouds:
1. Smoke or dust appearing in the cockpit.
2. An acrid odor similar to electrical smoke.
3. Multiple engine malfunctions, such as compressor stalls, increasing EGT, torching from tailpipe, and flameouts.
4. At night, St. Elmo’s fire or other static discharges accompanied by a bright orange glow in the engine inlets.
5. A fire warning in the forward cargo area.
e. It may become necessary to shut down and then restart engines to prevent exceeding EGT limits. Volcanic ash may block the pitot system and result in unreliable airspeed indications.
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The FAA seems not to take the threat lightly.
I, personally, would follow their lead.
Is this why ozone hole appeared on northern pole right after?
Having had direct personal experience with volcanic ash by being downwind of the Mt St Helens eruption when she blew, and seeing what the ash did to cars, and trucks in Yakima and eastern Washington. No no no! You won’t catch me flying anywhere near an active volcano if I can help it, much less down wind. In fact, I can tell you that being on the the ground in freshly fallen volcanic ash is no picnic either. The damned ash gets into everything. No matter how well you try to protect yourself, there are no orifices, cracks, or wrinkles, in the human body that the irritating, and gritty stuff won’t find it’s way into.
And Eyjafjallajökull’s just a pup. The big dog to be afraid of is Katla. And if eruptions of the past are any indicator they tend to wake each other up. The worst is yet to come.
I once had a post removed for breaking house rules on the BBC website when I typed the name. Either the BBC swear-checker or the moderators considered it a word too far.
The article in question was a football report where the writer compared the England football manager to Vesuvius, and I then compared the writer to Eyjafjallajökull.
Well, I spent a while listening to the name being spoken by Icelanders on a TV show about the volcano. Maybe it’s my broken American ears, but to me it was pretty simple after a few passes. What they were saying sure sounded like:
Eye-Ya-Fa-Ya’ll-a-yokel (and that sure looks like it would map to the spelling too).
Then again, just saying “Volcano unpronounceable” is widely recognized…