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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I took a look at that, you're right, alot of glacial melt took place.
Tomorrow, the skies are supposed to clear, and we'll get a better idea of what the volcano is doing. It has been shrouded most of the afternoon.
There must be an ancient fault line there . There have been a number of quakes from 1990-present:
Well there you go then... The earths crust has more cracks on it than an old cowboys skin.
AOI/XX/XL
MARK
12N/70W
It must be an ancient plate that helped to form the Appalachian mountains eons ago. As old as Floodman!
Looks like the Windward Islands may receive some more rain!!
Would be great, but models (GFS) don't show this.
Floyd caused widespread flooding and flood damage throughout the state.
Nope....far too deep for anyone to feel.
It really may be a pretty nice setup for such an event to occur during the first week of May.
That is a good thing!
The Euro doesn't really have anything on the surface (only goes out to 240 hours though), but it does show the same reversal from troughing to ridging over the Caribbean, which is a much more favorable environment for tropical mischief.
That's actually Indonesia and not Australia.
No, it's not that kind of volcano. Katla could, but this one not so much. The ash wasn't blasted high enough.
At this current state of the Iceland eruption, probably not, as it is a relatively small eruption at the 65N parallel, prevailing winds will keep whatever aerosols that are present way up north, far away from the Tropics.
However, if there is a larger eruption, things may change, but at this moment, there is no sign that will occur.
Yes, it appears the GFS shows a broad monsoon gyre to develop, with the system following the advancement of the MJO eastward. Potentially our first true AOI if the GFS continues to be consistent.
by joe.
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Most of the ash is being dispersed around Europe and parts of Russia, A big Low pressure area would help wash a good part of the ash out of the sky.
Thanks Levi!
nice spot on the sun
They have been strongly disagreeing all winter long due to the El Nino, at least during the times when I actually checked. To me the GFS makes a bit more sense because the Kelvin Wave currently moving across the eastern Pacific argues for upward motion near central America around that time.
not much....
Hiya Amy
A good rain would indeed wash the ash away provided the rain level starts above the ash. Believe it or not though, with enough ash it can basically rain mud. A good rain is the best way to clear the air of the smallest ash that may still remain after the main ash events passes.
That's true, since the east Pacific is climatologically favored early-on, but upper-level conditions are forecasted to be favorable over both areas, so there is as much of a chance for Caribbean mischief as EPAC mischief.
From what each forecast a week ago GEFS was more right but neither really had a handle on it.
Or maybe 2 systems form, one in each basin?
That is true:
Just my two cents fellas :)
mmmmm less dust
Edit: Ummm, here's another link unrelated to the first.
TXC375-381-210045-
/O.NEW.KAMA.TO.W.0002.100421T0022Z-100421T0045Z/
BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE AMARILLO TX
722 PM CDT TUE APR 20 2010
THE NATIONAL WEATHER SERVICE IN AMARILLO HAS ISSUED A
* TORNADO WARNING FOR...
SOUTHWESTERN POTTER COUNTY IN THE PANHANDLE OF TEXAS.
NORTHWESTERN RANDALL COUNTY IN THE PANHANDLE OF TEXAS.
* UNTIL 745 PM CDT
* AT 720 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS HAVE
DETECTED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THE
MOST DANGEROUS PART OF THIS STORM WAS LOCATED NEAR BUSHLAND...OR
ABOUT 15 MILES WEST OF AMARILLO...MOVING SOUTHEAST AT 10 MPH.
* SOME LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE BUSHLAND.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A TORNADO HAS BEEN CONFIRMED! TAKE COVER IN A STURDY BUILDING NOW.
MOBILE HOMES AND VEHICLES ARE NOT SAFE.
TO REPORT SEVERE WEATHER...PLEASE CALL THE NATIONAL WEATHER SERVICE
AT 8 0 6 3 3 5 1 1 2 1.
ECMWF is closest to the GEFS
wow, thats a beaut of a supercell
The cell has weakened, Jim Cantore at TWC has been watching it, a large tornado was spotted about 5 miles west of the town of Bushland, TX. To make matters worse, it was "rain wrapped".
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