Why Southeast Greenland's glaciers have slown down since 2005

By: Dr. Jeff Masters , 3:57 PM GMT on December 15, 2009

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I'm in San Francisco for the annual meeting of the American Geophysical Union, the world's largest gathering of climate scientists. I saw ten or so great talks yesterday (and five really boring ones!) Here's a summary of the the most interesting talk I heard yesterday:

If you plan on owning ocean front property after the year 2050, you should pay close attention to the glaciers In Greenland. Greenland holds enough ice to raise global sea level by over 20 feet (6.5 meters), should its ice cap completely disintegrate--though such an event would likely take centuries to occur. Still, should the climate warm 2°C or more this century, partial melting of the Greenland Ice Sheet could readily raise global sea level by a meter or more by 2100. That's why scientists reacted with concern during 2003 - 2005, when all of the glaciers in southeastern Greenland accelerated in synchrony to speeds 30% to 210% faster than they had flowed in 1996. As they sped up, the glaciers began dumping huge amounts of ice into the ocean off the coast of southeast Greenland, more than doubling Greenland's contribution to global sea rise, to .57 mm/year. Would the glaciers keep accelerating, bringing about an increasing disintegration of the Greenland Ice Sheet? Nobody knew, since computer models of glacial dynamics were (and still are) in a primitive state.


Figure 1. Helheim Glacier in southeast Greenland, in three images captured in 2004, 2005, and 2006. The glacier accelerated significantly in 2005, and the face of the glacier retreated 5 km inland (middle frame) compared to 2004. However, by the summer of 2006, the acceleration ceased, the the glacier returned back to its 2004 position. Image credit: Ian Howat, University of Washington.

Well, it turned out that 2005 was the peak of the glacial acceleration event. The glaciers in southeast Greenland have returned to where they were eight or nine years ago--still causing a net loss of mass that is raising global sea level, but not as fast as in 2003 - 2005. In a talk titled, "Ocean regulation of glacier dynamics in south-east Greenland and implication for ice sheet mass changes", Tavi Murray and colleagues from the UK's Swansea University presented a plausible theory for why this strange synchronous speed-up and slow-down occurred. Using satellite, aircraft, and surface observations, the researchers found that air temperatures in the region did not vary much over 2003 - 2005 (Figure 2). Thus, a major increase in temperature could be ruled out as the cause of the glacier surge. However, study of the ocean temperatures near the coast revealed strong clues that ocean currents were responsible for the surge.

Figure 2. Ocean currents off the east coast of Greenland feature the cold East Greenland Coastal Current flowing north to south (white arrows) and the warm Irminger Current flowing south to north (red arrows). Image credit: Arctic Climate Impact Assessment.

Ordinarily, the southeast coast of Greenland features a cold water current flowing north to south, called the East Greenland Coastal Current (EGCC). Much of the cold water for this current is supplied by melting of the 14 glaciers in southeast Greenland that empty into the sea (two of these glaciers, Kangerdlugssuaq and Helheim, represent 35% of east Greenland's total glacial discharge). A few hundred kilometers offshore, a warm water current called the Irminger Current flows the opposite direction, bringing warm water from the North Atlantic northward. In 2003, it happened that weather conditions over Greenland brought an unusually low amount of run-off of precipitation. With little new mass pushing the glaciers seaward, the glaciers responded by greatly reducing the amount of ice they dumped into the ocean by the shore. As a result, the East Greenland Coastal Current slowed down and warmed, which allowed the warm Irminger Current to advance towards the coast, warming the coastal waters even more. All that warm water near the coast began melting the glaciers where they reached the sea, causing the glaciers all along the southeast coast of Greenland to accelerate and rapidly thin between 2003 - 2005. By 2006, the thinning glaciers had dumped so much new ice into the ocean near the coast that the waters cooled and the East Greenland Coastal Current re-established itself. This cooled the glaciers at their marine termination points and slowed down the glacial surge, putting the glaciers back where they had been before 2003. This is a classic example of a negative feedback process--a change in weather conditions which generates a response, but the response creates conditions that tend to dampen the response.


Figure 3. Average temperatures for the only station in southeast Greenland with a century-long temperature record, Angmagssalik (called Ammassalik on the map in Figure 2). Temperatures in southeast Greenland during the 1930s and 1940s were similar to today's temperatures, suggesting that glacial surges like we witnessed in 2005 may have also occurred in the 1930s and 1940s, before we had monitoring capability. Image credit: NASA Goddard.

Commentary
As I commented in my previous post, Arctic sea ice loss appears to have created a new atmospheric circulation pattern that brings more warm air in the Arctic, creating a positive feedback loop that causes even more sea ice loss. This positive feedback loop was a bad news surprise that our climate models did not predict. Now we have evidence of a good news surprise that no model predicted--a negative feedback loop that acts to keep the southeast portion of Greenland's Ice Sheet from runaway glacial acceleration. We can expect many more surprises--good and bad--over the coming decades, as our climate responds to the huge shove human activities are giving it.

Ricky Rood in Copenhagen
Our Climate Change expert, Dr. Ricky Rood, is in Copenhagen for the COP15 climate change treaty negotiations. His latest post, called Have you no sense of decency, sir, at long last? makes for very interesting reading on how the U.S. is "wasting its intellect and time on disruptions designed to play to people at home".

Next post
I'll have another post from the AGU meeting Thursday or Friday this week.

Jeff Masters

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Quoting Jeff9641:


I agree the problem is it has been difficult to get cold airmasses into the penisula of Florida. We've been getting a lot of rain but that's it.

Well its only Decemeber. Here Feb is "usually" our coldest month.
Member Since: August 2, 2006 Posts: 0 Comments: 1240
962. xcool
all i can said gfs keeping show snow
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Quoting VAbeachhurricanes:


drak i love you hahahaha :D

Ahhh, sookie sookie now. Giggles, just kiddn
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959. xcool
The December to Remember is about to fire up in a way that makes this holiday season the most memorable one in many a year weatherwise.

by Joe Bastardi
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Quoting Drakoen:


According to the GFS and ECMWF I would look for a more snow event than rain event as the models show a 1000mb-500mb thickness of 540dm off the coast as well as the 850mb 0C isotherm. I see the potential for heavy snow in Virginia and back towards the Appalachians.


drak i love you hahahaha :D
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Quoting Bordonaro:






GFS 12-28-09, 276 HRS out, 2M temp, 10M wind

Hopefully this holds true. Ill be watching it.
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Quoting Jeff9641:


Maybe after Christmas. Here in Central Florida not a chance but where you live maybe so. The southern branch is really going to get charged up later next week with the potential for intense low pressure areas moving from the GOM to New England.

Well I think if yall were to get any snow this will be the year.
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Quoting alaina1085:

I want snow for the gulf states. lol.






GFS 12-28-09, 276 HRS out, 2M temp, 10M wind


For a larger pic, right click on image, right click on properties, cut and paste URL address into your browser and voila' full image!!!
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Just received this interesting weather advisory:

...Potential for severe storms and coastal hazards on Friday...An area of low pressure is expected to develop over the western Gulf of Mexico on Thursday. This low is then expected to intensify as it moves east across the northern Gulf Coast Thursday night and then across the northern Florida Peninsula on Friday. Ahead of the low an increasing moist southerly wind flow will develop over west central and southwest Florida Thursday night and Friday. This increasing southerly flow will help to build seas over the adjacent Gulf waters. The building seas will generate large breaking waves and dangerous rip currents along and high surf along area beaches on Friday with above normal tides possibly causing some coastal flooding at times of high tide on Friday. The strong southerly wind flow and increasing seas will make for hazardous boating conditions over the Gulf waters and inland water ways...and mariners may want to postpone trips into the Gulf until conditions improve.

As the low pressure area approaches a more favorable environment for severe storms will develop over west central and southwest Florida late Thursday night into Friday. As the low moves east northeast across the Northern Peninsula during the day on Friday a squall line will likely develop along and ahead of a trailing cold front over the adjacent Gulf waters early Friday morning with the line of storms likely to affect the region from mid morning through the afternoon and early evening hours. At the current time sufficient low level moisture combined with strong prefrontal convergence...sufficient deep layered shear and a strong low level jet may help to produce organized storms containing damaging winds and possible isolated tornadoes and marine waterspouts. In addition some locally heavy rainfall and deadly lightning strikes will accompany the storms as they move across the region. In the wake of the cold front a brisk northwesterly wind flow will usher in a much cooler and drier air mass with below normal temperatures expected across the region through the upcoming weekend...with some near freezing temperatures possible over the Nature Coast by Sunday night into Monday.

In addition to the cooler temperatures the brisk northwest wind flow will keep sea elevated over the adjacent Gulf waters with hazardous boating conditions continuing.

All residents and visitors of west central and southwest Florida should remain alert to rapidly changing weather conditions during Thursday night into Friday. Stay tuned to NOAA Weather Radio or your local media for further updates on this developing weather situation.
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I like that map XCool. That would be crazy...lol.
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951. xcool


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Quoting Drakoen:
The ensemble members of the GFS have trended westward with snow axis stretching considerably farther westward.

I want snow for the gulf states. lol.
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Quoting NEwxguy:
941. Bordonaro
Would not be surprised to see the cape and the islands get snow out of this.


By tomorrow's computer run, you should have an excellent idea, who is gonna get SLAMMED

LATEST 12Z GFS 96HRS OUT, 12-20-09, 2M temp, 10M wind (Surface Temps/Winds)


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The ensemble members of the GFS have trended westward with snow axis stretching considerably farther westward.
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Quoting Jeff9641:


He has been getting me 40 to 60 points per week which is fantastic because of him I'm in the playoffs. Once you get into it yes it can be addictive. Sunday's are spent watching football and drinking cocktails with the guys.

Awesome. My sunday's are spent watching some good ol football as well. So are my monday nights and thursday nights lol. And apparently this saturday night (you know, when the saints slaughter the cowgirls.. I mean boys)
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Quoting VAbeachhurricanes:
Drak, thank god your here :). i had a question for ya.

So yesterday the NWS said that this weekend would be 36 degrees all rain, that has dropped to 33 and rain/snow, what are the odds that this trend will continue and they will call for all snow?


According to the GFS and ECMWF I would look for a more snow event than rain event as the models show a 1000mb-500mb thickness of 540dm off the coast as well as the 850mb 0C isotherm. I see the potential for heavy snow in Virginia and back towards the Appalachians.
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941. Bordonaro
Would not be surprised to see the cape and the islands get snow out of this.
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Quoting Bordonaro:


CLOSE CALL!! GFS 90HRS 12-20-09 2M temps, 10M winds



thats right over me... i hope to god it comes true.
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Quoting NEwxguy:
Still doesn't look like up here in New England we have to worry about this coastal low,but something about this setup and where the trough sets up is making me nervous,but then in New England you always wonder about any coastal low until it moves out.


CLOSE CALL!! GFS 90HRS 12-20-09 2M temps, 10M winds



NCEP 18Z report, 72 HR Loop, 850MB temps/6 hr precip link below:

Link
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Quoting Jeff9641:


Drew is my fantasy quaterback and he is killing it for me this year.

I need to learn how to play fantasy football. I know I would be addicted.
And by kill you mean a good kill or bad kill? lol.
Member Since: August 2, 2006 Posts: 0 Comments: 1240
Drak, thank god your here :). i had a question for ya.

So yesterday the NWS said that this weekend would be 36 degrees all rain, that has dropped to 33 and rain/snow, what are the odds that this trend will continue and they will call for all snow?
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Still doesn't look like up here in New England we have to worry about this coastal low,but something about this setup and where the trough sets up is making me nervous,but then in New England you always wonder about any coastal low until it moves out.
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Yo! Grothar needs some assistance. I just uploaded some pictures, but they do not appear as Wunderphotos, just My pictures. How do I get them there?
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Well, ummmmm, I'm an Irish Fan. Starting to feel like a Cubs Fan though, lol. Someday, they'll be back, I think :-/
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It seems as though the ECMWF and GFS have trended back westward with the coastal storm bring snow to portions of South Carolina, North Carolina and Virgina with the activity primarily south of the Mason-Dixon Line.
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Quoting TheCaneWhisperer:



I guess Florida is number 2 because they keep winning and have reason to party?


Nope they live in a swamp and that's the only thing to do. Also without Alcohol intake swamp gas can cause severely low grades. lol j/k.
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Quoting alaina1085:

Well im so glad that was informative. lol. Basically they have no clue. Nice.


Yea your right. LSU is a strong academic school as well. They used to be on that list but guess things have calmed down since all the school shootings and such.


Computer models are only good for about 3 to possibly 7 days! However, computer models past day 7 are basically, in a nutshell, useless!

However, for entertainment purposes only, GFS models are indicating a good shot of Arctic air, a coastal Low developing on 12-27, bring snow/sleet/freezing rain to large portions of TX, LA and on 12-28, that moves into the SE US

12-27-09 @252 hrs, GFS 2M temps, 10M winds




GFS @272 hrs, 12-28-09, 2M temps, 10M winds


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Quoting TheCaneWhisperer:



I guess Florida is number 2 because they keep winning and have reason to party?


haha, penn state its too cold out only thing to do is stay in and party
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Quoting StormChaser81:


Here's the Princeton Review's complete list of top party schools:

1. Pennsylvania State University
2. University of Florida
3. University of Mississippi
4. University of Georgia
5. Ohio University
6. West Virginia University
7. The University of Texas at Austin
8. The University of Wisconsin-Madison
9. Florida State University
10. University of California-Santa Barbara
11. University of Colorado-Boulder
12. University of Iowa
13. Union College
14. Indiana University
15. DePauw University
16. University of Tennessee
17. Sewanee: The University of the South
18. University of North Dakota
19. Tulane University
20. Arizona State University


Where is Purdue j/k

Better luck next year...lol



I guess Florida is number 2 because they keep winning and have reason to party?
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Quoting VAbeachhurricanes:


big ten quater backs are owning, henne, brady, brees, orton, robinson as a RB. all doing well


yeah we seem to produce some good ones
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Quoting tornadodude:
#1 reason Purdue is better:

Drew Brees :P


big ten quater backs are owning, henne, brady, brees, orton, robinson as a RB. all doing well
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Member Since: July 3, 2005 Posts: 423 Comments: 127807
Quoting Patrap:

Shes healing well,..thanx for asking.




Glad to hear it.
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Quoting alaina1085:
Pat, How is your daughter doing?

Shes healing well,..thanx for asking.



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Quoting tornadodude:
#1 reason Purdue is better:

Drew Brees :P


WHO DAT
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GFSx 25 December/9day GFSx SL Pres/Prec Plot
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#1 reason Purdue is better:

Drew Brees :P
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Pat, How is your daughter doing?
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Quoting Patrap:
LSU being a walking Campus,has strict Policing of traffic,and if you get a DWI,..well,its expensive,..

And Alcohol is strictly controlled at Death Valley.

If U aint 21,U aint a drinking.




This is very true.
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Quoting VAbeachhurricanes:


most of those schools also have 40K plus going there, which helps alot.


Ya thats true, the more people the more bad apples in the mix. But i use to party with my professors in Graduate school, so go figure. You would think they would have calmed down by them, but a college town is still a college town, bottoms up.
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LSU being a walking Campus,has strict Policing of traffic,and if you get a DWI,..well,its expensive,..and your on Campus driving days are over,
Period.

And Alcohol is strictly controlled at Death Valley.

If U aint 21,U aint a drinking.



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Quoting StormChaser81:



Maybe a good thing not making the list =), but most of the schools on the list are very academic strong.


most of those schools also have 40K plus going there, which helps alot.
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Quoting Patrap:
NWS NOLA Paragraph of ,hmmmmmm?

After our Thursday night/Friday system pushes east we will start to dry out
but by Sat afternoon/evn a strong middle level disturbance will push through
the lower MS valley and this will usher in a much drier and cooler
airmass. Northwest flow will remain over the region the first half of next
week and this is generally a dry scenario for our region. The northwest
flow aloft is also favorable for US to get some decent shots of cold
air into the region. Temperatures will likely be at to just below normal
for much of the extended. The models begin to diverge late Tuesday and
more so Wednesday so at this time your Christmas travel forecast is still
very much up in the air. /Cab

Well im so glad that was informative. lol. Basically they have no clue. Nice.

Quoting StormChaser81:



Maybe a good thing not making the list =), but most of the schools on the list are very academic strong.

Yea your right. LSU is a strong academic school as well. They used to be on that list but guess things have calmed down since all the school shootings and such.
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Quoting alaina1085:


Dang, I figured LSU would be on that list... guess not.



Sighs... Im seriously sick of the rain.


Maybe a good thing not making the list =), but most of the schools on the list are very academic strong.

I almost think the harder they party the better they stand academically, maybe they release more pressure.
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NWS NOLA Paragraph of ,hmmmmmm?

After our Thursday night/Friday system pushes east we will start to dry out
but by Sat afternoon/evn a strong middle level disturbance will push through
the lower MS valley and this will usher in a much drier and cooler
airmass. Northwest flow will remain over the region the first half of next
week and this is generally a dry scenario for our region. The northwest
flow aloft is also favorable for US to get some decent shots of cold
air into the region. Temperatures will likely be at to just below normal
for much of the extended. The models begin to diverge late Tuesday and
more so Wednesday so at this time your Christmas travel forecast is still
very much up in the air. /Cab
Member Since: July 3, 2005 Posts: 423 Comments: 127807
Quoting StormChaser81:


Here's the Princeton Review's complete list of top party schools:

1. Pennsylvania State University
2. University of Florida
3. University of Mississippi
4. University of Georgia
5. Ohio University
6. West Virginia University
7. The University of Texas at Austin
8. The University of Wisconsin-Madison
9. Florida State University
10. University of California-Santa Barbara
11. University of Colorado-Boulder
12. University of Iowa
13. Union College
14. Indiana University
15. DePauw University
16. University of Tennessee
17. Sewanee: The University of the South
18. University of North Dakota
19. Tulane University
20. Arizona State University


Where is Purdue


HELL YEA PSU BABY!
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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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