Tracking the ash from the ‘unpronounceable’ volcano

From the FECYT – Spanish Foundation for Science and Technology

Scientists ‘read’ the ash from the Icelandic volcano 2 years after its eruption

The models aim to predict the evolution of volcanic ash clouds, like the one emitted by Eyjafjallajökull. Credit: FLEXPART/NILU.

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.

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43 thoughts on “Tracking the ash from the ‘unpronounceable’ volcano

  1. 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…

  2. 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.

  3. 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’.

  4. “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.

  5. Dennis Cox says:
    May 12, 2012 at 8:43 am

    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 got the “yokel” part a few years ago, during the first eruption. More work needed.

  6. 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.”

  7. 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.

  8. “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 ;)

  9. 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.

  10. 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.

  11. 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.

  12. 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.
    =============
    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.

  13. 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.

  14. 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.”

  15. 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.

  16. 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.
    =============
    The FAA seems not to take the threat lightly.
    I, personally, would follow their lead.

  17. 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.

  18. 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.

  19. 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…

  20. Verity Jones says:
    May 12, 2012 at 10:05 am

    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

    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.

  21. 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.

  22. 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?

  23. 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.
    ========
    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.

  24. sabretoothed says:
    May 12, 2012 at 5:33 pm
    Is this why ozone hole appeared on northern pole right after?
    ======
    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.

  25. 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?

  26. 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.

  27. 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,

  28. 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.

  29. 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.

  30. OK, this isn’t Icelandic, but it relates to we speakers of English having trouble with other languages. Enjoy!

  31. 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”. . . .

    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

  32. 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 . .. .

  33. 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.

  34. 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
    You +1’d this publicly. Undo
    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.

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