Forecasting the volcanic ash plume of Iceland's volcano

By: Dr. Jeff Masters , 2:45 PM GMT on April 19, 2010

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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

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Quoting Chicklit:
That's not strategy. It's lunacy.


I'll try to find an even more bizarre strategy for you. Give me a few minutes... :)
Member Since: August 26, 2006 Posts: 10 Comments: 3753
Quoting Stormchaser2007:
Nino 3.4 now at .6

WOW
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Nino 3.4 now at .6

Member Since: June 9, 2007 Posts: 4 Comments: 15921
Quoting kimoskee:
Okay... don't know what's up the link but let's try that again

http://www.msnbc.msn.com/id/36645958?GT1=43001



Okay... officially giving up trying to post link. SORRY!!!!
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That's not strategy. It's lunacy.
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Okay... don't know what's up the link but let's try that again

http://www.msnbc.msn.com/id/36645958?GT1=43001

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LOL...
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MSN has some amazing photos of the volcano
not as good as the ones on this blog... but good nonetheless.

Here's the link
http://www.msnbc.msn.com/id/36645958?GT1=43001

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Quoting VAbeachhurricanes:


im assuming strap yourself to the flagpole? only thing is what if that house flies toward your flag pole?


I don't doubt things will be flying, at least for awhile.

But if a Cat 5 landfalls in Pass Christian, it will be the storm surge to really worry about.

If you figure 30 minutes for the water to rise above your head once the inner eyewall crosses shore, then you're basically doing both...floating up with the flagpole and dodging roofs and such.

Granted, this little flagpole is not much of a survival strategy, but it is a strategy none-the-less.
Member Since: August 26, 2006 Posts: 10 Comments: 3753
Quoting Drakoen:


Out of all those graphics 2010 is the most alarming.
With the current signs of where the Bermuda high is building, it looks like it's going to be a messy year for the SE United States.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting VAbeachhurricanes:


yeah but look at close to home compared to the two years, much cooler water


Which will easily warm up to support major hurricanes as we get into the heart of the season.
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Quoting Drakoen:


Out of all those graphics 2010 is the most alarming.


yeah but look at close to home compared to the two years, much cooler water
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Quoting dayton:
Could someone please talk about the severe weather outlook for the midwest this week?The SPC had dropped the "Slight" Severe Weather for Th 4-22 due to the system slowing down. Computer models are in disagreement on the timing and severity.

The Area Forecast Discussion out of NWS Ft Worth, TX brings the CA storm through North TX either Friday night or sometime on Saturday.

We need to wait till Tu/We to get a better idea. Severe weather is still a decent possibility for Fr-Sa in the S Plains and the Midwest. Stay tuned :o).
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Some favorable conditions do exist in the Atlantic.

Keep in mind its mid April...
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Quoting CycloneOz:


im assuming strap yourself to the flagpole? only thing is what if that house flies toward your flag pole?
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Quoting Levi32:


Unfortunately those maps only go back to 2002. We still have the OSDPD ones though.

April 17th 1998:



April 19th 2005:



April 19th 2010:




Out of all those graphics 2010 is the most alarming.
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Quoting Greyelf:

It looks like a balrog! Golden Geek Award to those who know what I mean.

To be awarded, doubtless, in Moria, in Khazad-dum.
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Quoting CycloneOz:


The only difference I see in the two images is that the water around NOLA was warmer in 2005.

Of course, that could have been a Patrap anomaly...some type of nasty, personal discharge into the Gulf.



How Quaint..

Saw a lot in 2005,..more than most would care to remember.

Ill pass that on to some family members lost as well.

..and I didnt start posting till April of 06..
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Quoting StormW:


Levi, can you pull up 1998?

I'm out for a little...gotta little boy to pick up from school.


Unfortunately those maps only go back to 2002. We still have the OSDPD ones though, but they're daily, not monthly averages. 1998 is the next closest SST profile analog, with the biggest difference being the state of the El Nino at this time that year.

April 17th 1998:



April 19th 2005:



April 19th 2010:


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Quoting StormW:


Levi, can you pull up 1998?

I'm out for a little...gotta little boy to pick up from school.
This is all I found:

Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting Chicklit:
Hi Dan. The trip took about 40 hours.
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?!


OMG, on the deck, across the Channel in April, brrrrrrr.

What's that saying, "be careful what you wish for". Actually I bet she realized what she WAS capable of after this trip.
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Quoting Levi32:
This is the SST comparison I posted. You can't get any more similar than that. 2005 is now the most similar SST profile analog we have.

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:


And we are still warmer along the African Coast and the Caribbean. We are just a bit cooler in the GOM.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting StormW:


Aye!
Drak, liked that SST loop you posted. Guess we ain't gettin a break this season.


Nope, It appears the 26C isotherm will be expanding northward.
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Quoting CycloneOz:


I happily remember the BIG ONE you posted that night a few weeks ago that almost knocked me out of my chair when I refreshed the screen. LOL!


Yes, it is my signature texting move....lol.
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Quoting Levi32:


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.


I happily remember the BIG ONE you posted that night a few weeks ago that almost knocked me out of my chair when I refreshed the screen. LOL!
Member Since: August 26, 2006 Posts: 10 Comments: 3753
This is the SST comparison I posted. You can't get any more similar than that. 2005 is now the most similar SST profile analog we have.

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:


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Quoting CycloneOz:


DOOM!


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.
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Quoting CycloneOz:


DOOM!
Lol, I forgot you. Your one of the best too.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Hi Dan. The trip took about 40 hours.
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?!
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We continue to be warmer than 2005 in the MDR at this time.
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Could someone please talk about the severe weather outlook for the midwest this week?
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Quoting MiamiHurricanes09:
Something odd is going on, all of the best bloggers are on:

*Drakoen
*Levi32
*StormW
*Patrap
*PcolaDan

Sorry to anyone I may of forgotten. All bloggers are excellent except for the doomcasters, those people are just wierd, lol.


DOOM!
Member Since: August 26, 2006 Posts: 10 Comments: 3753
Quoting StormW:


I wish!
lol
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting Chicklit:
Yeah, my neice was on a student-exchange in Madrid from England with 34 other students. Fortunately, four, quick-thinking teachers accompanying them appraised the situation when they were due to fly out Saturday and reacted quickly by chartering a bus and then arranging for a ferry. Had they waited, those children would have been stranded!
Teachers are used to thinking on their feet and reacting in intelligent ways to unforseen circumstances. Go teachers!


Good for them. You're right, they would be stuck from everything I have read. For the kids it was probably a great adventure.
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Member Since: August 26, 2006 Posts: 10 Comments: 3753
Quoting KEEPEROFTHEGATE:
whats up with cano cams i am getting nothing


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.
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Member Since: July 15, 2006 Posts: 174 Comments: 54420
Quoting Bordonaro:

It's a meeting of the minds!!
Lol, you too Bordonaro, your a great blooger. And I almost forget about the "KEEPEROFTHEGATE"

-----------------

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
Member Since: September 2, 2009 Posts: 130 Comments: 21194
The European, although it only goes out to 240 hours, is also showing a reversal from troughing to ridging over the Caribbean.

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Yeah, my neice was on a student-exchange in Madrid from England with 34 other students. Fortunately, four, quick-thinking teachers accompanying them appraised the situation when they were due to fly out Saturday and reacted quickly by chartering a bus and then arranging for a ferry. Had they waited, those children would have been stranded!
Teachers are used to thinking on their feet and reacting in intelligent ways to unforseen circumstances. Go teachers!
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Don't include me with that group. They know their weather. I have to feel it on my head to know if it's raining. I do keep up with other events suck as the volcano when they happen. Oh and of course, some levity when things get tense sometimes.
Member Since: August 22, 2008 Posts: 12 Comments: 6010
whats up with cano cams i am getting nothing
Member Since: July 15, 2006 Posts: 174 Comments: 54420
so we finally have some "normal" temps this week, down to the 60's as opposed to the 80's we had last week
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good late afternoon all
Member Since: July 15, 2006 Posts: 174 Comments: 54420

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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