Forecasting the volcanic ash plume of Iceland's volcano
The eruption of Iceland's volcano with the unpronounceable name, Eyjafjallajökull, has virtually ceased over the past few hours, with ash only reaching up to 6,000 feet (1800 meters), according to the latest advisory from the UK Met Office. Lightning images from UK Met Office show no new lightning strikes from the volcano's plume since midnight local time today. The relatively small amount of ash present at low altitudes will probably not be able to make it all the way to mainland Europe before falling to the surface and dissipating, since 6,000 feet is below the altitude that the strong winds of jet stream blow. Wednesday through Sunday, the volcano emitted a towering cloud of volcanic ash 6 - 11 km (20,000 - 36,000') high in the air from its 1666 meter (5500') high peak. The jet stream blows strongly at that altitude range, which allowed for efficient transport of the ash cloud to mainland Europe.
Figure 1. Lightning lights up the night sky in this photo of Eyjafjallajökull's eruption taken on April 16, 2010. Ash particles colliding together separate electric charge, much as ice particles in a thunderstorm do, leading to spectacular lightning displays. Image credit: Marco, Fulle, Stromboli Online.
Forecasts of the movement of the ash cloud are made using trajectory models, which have a number of uncertainties to consider. Firstly, the amount of ash ejected by the volcano is highly uncertain, since our measurements of this quantity are limited. Secondly, the models must compute how high the ash cloud will rise (plume rise), based on the best available measurements of atmospheric stability. Since upper air-observations are taken just twice daily by a very coarse network of balloon soundings, our knowledge of the stability is rather crude. Finally, the trajectory models use forecast winds from a global model such as the GFS model to predict where the plume may go. The forecast winds from this model do not capture much of the complicated structure of the wind field over Europe, leading to a rather fuzzy approximation of where the ash will go. Nevertheless, these models have in general done a respectable job forecasting where the ash from Eyjafjallajökull will go over the past few days.
Figure 2. Cross section of the atmosphere over time over Paliseau, France, on April 16, 2010, as observed using ground-based lidar. Image taken using a 532nm cross polarization NFOV telescope. Note how the ash layer sinks closer to the ground as time progresses, as gravity makes the ash sink to the ground. There may also be some atmospheric subsidence occurring (downward moving air due to large-scale atmospheric processes.) Image credit: Ray Hoff, World Meteorological Organization's Global Atmosphere Watch's Aerosol Lidar Network (GALION).
For the next few days, these models continue to indicate that northwest winds at the jet stream level will continue to affect Iceland. As a result, Spain, Portugal, and Greece will offer the best locations to fly from. The northwesterly winds are expected to continue for the remainder of the week, thanks to an upper-level trough of low pressure over northern Europe. On Saturday April 24, the ECMWF model predicts that the trough will slide eastwards, and a ridge of high pressure will build over Europe. This will bring upper-level winds out of the southwest to Iceland, directing any volcanic ash northwards over the North Pole. Thus for the remainder of this week, expect continued ash clouds over much of Europe if the volcano resumes significant eruptions. But by next Sunday, the ash over Europe should decline considerably. For the latest one-day forecasts of where the ash cloud is expected to go, consult the UKMET Office. The Rhenish Institute for Environmental Research at the University of Cologne also has some excellent simulations from an atmospheric dispersion model of Eyjafjallajökull's eruption plume. The Norwegian Institute for Air Research runs a computer trajectory model called FLEXPART that has 1-day forecasts showing a cross section of the atmosphere. NOAA's Air Resources Laboratory (ARL) lets you perform your own model run using their HYSPLIT model, going out up to 48 hours, using the GFS model as input.
Figure 3. NASA's Aqua satellite captured this image of the eruption at 1:20 UTC on April 17, 2010. Image credit: NASA Earth Observatory.
Links
An excellent source of links of information on the eruption is available at http://islande2010.mbnet.fr/2010/04/eyjafjallajok ul-links-liens-a-propos-de-leyjafjallajokul/. My post on Thursday discusses the likely non-impact of this eruption on Earth's climate. Finally, we need to be keeping an eye on earthquake activity at the dangerous Katla volcano next to Eyjafjallajökull. If that volcano blows, it could mean dwarf the headaches caused by Eyjafjallajökull.
Jeff Masters
Reader Comments
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Yup, unfortunately...
We've had a negative NAO for most of the winter, which results in a weaker Azores High. A weaker Azores High results in a weaker pressure gradient which results in slower trade wind speeds over the tropics. The Azores High has been weak and pushed south of where it usually is all winter long, and that is bad news regarding SSTs.
Link
Interesting westward bulge in the Loop Current north of the Yucatan in that forecast.
AMAZING!!! I like living on planet earth.
This pattern on the GFS would likely produce a negative SOI burst as well over the next couple weeks, which is expected in response to the huge positive burst we are currently experiencing.
kinna looks like the monster in Forbidden Planet
Figure 1. AOML Sea Surface Temperatures April 15, 2010
Figure 2. Surface Winds Speeds (top) and Surface Wind Speed Anomalies (bottom)
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Schools in chaos after teachers and pupils stranded
Schools across the country closed or suspended classes today as hundreds of teachers were stuck abroad because of disruption to flights
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* Jessica Shepherd, Sarah Boseley, and Richard Wray
* guardian.co.uk, Monday 19 April 2010 21.32 BST
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The runway at Edinburgh airport where flights are cancelled for a fifth day
The runway at Edinburgh airport where flights are cancelled for a fifth day. Photograph: Jeff J Mitchell/Getty Images
Schools across the country suspended classes and some closed today as hundreds of teachers remained stranded abroad because of the disruption to flights.
Protocol Education, an agency that provides schools with supply teachers, said it had been particularly busy dispatching extra teachers to schools in Manchester, Leeds, Essex and Bristol and had received four times the usual number of calls to its south London office.
At least two schools, in Gloucestershire and Derbyshire, were forced to stay shut on the first day of the summer term because of serious teacher shortages.
Three others – comprehensives in Birmingham and London – closed to 11- and 12-year-olds so that staff could concentrate on teenagers preparing for GCSE and A-level exams next month.
Scores of schools have resigned themselves to spending thousands of pounds on supply teachers until flights start getting through and the backlog is cleared.
Most schools were on their Easter break at the time of the eruption and many teachers were on holiday abroad, while others were leading school trips and have been stranded along with their pupils.
The temperature forecast for the next 2 weeks doesn't look great for the GOM SSTs either, but part of these cold anomalies are due to SSTs being colder-than-normal in the first place, moderating air temps to some degree.
*Drakoen
*Levi32
*StormW
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*PcolaDan
Sorry to anyone I may of forgotten. All bloggers are excellent except for the doomcasters, those people are just wierd, lol.
It's a meeting of the minds!!
It looks like a balrog! Golden Geek Award to those who know what I mean.
Teachers are used to thinking on their feet and reacting in intelligent ways to unforseen circumstances. Go teachers!
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Levi posted earlier a comparison of April 10, 2005 and April 10, 2010 SST's and I "urinated" in my pants when I saw that 2010 is warmer. LOL
Evidently the cams have been blocked outside of Iceland right now. I was just going to show another site, but it just went belly up. Too much traffic on their network possibly.
Good for them. You're right, they would be stuck from everything I have read. For the kids it was probably a great adventure.
Actually, I think they slept on the deck of the ferry in the cold, huddled by the engine!
My sister insisted she go because she said she wanted her to get "out of her comfort zone."
Fait accompli!
Ahhh...there is no place like home, is there?!
Heeeey, I'm supposed to do that lol. If we get a whole bunch of trolls this year, I'm gonna do that on a really hectic day and scare the hide off of them.
The biggest differences are that the gulf was warmer in 2005 and the PDO was also warm, instead of going cold like it is now.
April 10th 2005 SST Anomalies:
April 10th 2010 SST Anomalies:
Yes, it is my signature texting move....lol.
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