The climate is changing: the Arctic Dipole emerges
The dramatic loss of Arctic sea ice in recent years has created a fundamental new change in the atmospheric circulation in the Northern Hemisphere that has sped up sea ice loss and is affecting fall and winter weather across most of the Northern Hemisphere, according to several recent studies. Arctic sea ice loss peaks in September and October, exposing a large area of open water that heats the air above it. This extra heat has helped drive September - November air temperatures in the Arctic to 1°C (1.8°F) or more above average over about half of the depth of the lower atmosphere (Figure 1). This deep layer of warm air has grown less dense and expanded, pushing the top of the troposphere (the lower atmosphere) higher. The result has been a decrease in the pressure gradient (the difference in pressure) between the North Pole and mid-latitudes. With not as much difference in pressure to try and equalize, the jet stream has slowed down in the Arctic, creating a major change in the atmospheric circulation for the Northern Hemisphere.
Figure 1. Cross section of Arctic temperature anomaly from 1000 mb (the surface) to 300 mb (roughly, the height of the top of the lower atmosphere or troposphere). Cross section is taken along the Date Line (180°W), from 60°N latitude (left side) to the North Pole (right side), for September - November for the 12-year period 1998 - 2009. Three year averages were done to reduce the amount of year-to-year noise associated with natural variation. Other cross sections along different lines of longitude show similar results, though typically with more warming aloft and less warming at the surface. Image credit: NOAA/ESRL.
A new atmospheric pattern emerges: the Arctic Dipole
In a 2008 article titled, Recent radical shifts of atmospheric circulations and rapid changes in Arctic climate system Zhang et al. show that the extreme loss of Arctic sea ice since 2001 has been accompanied by a radical shift of the Arctic atmospheric circulation patterns, into a new mode they call the Arctic Rapid change Pattern. The new atmospheric circulation pattern has also been recognized by other researchers, who refer to it as the Arctic Dipole (Richter-Menge et al., 2009). The old atmospheric patterns that controlled Arctic weather--the North Atlantic Oscillation (NAO) and Arctic Oscillation (AO), which featured air flow that tended to circle the pole, now alternate with the new Arctic Dipole pattern. The Arctic Dipole pattern features anomalous high pressure on the North American side of the Arctic, and low pressure on the Eurasian side. This results in winds blowing more from south to north, increasing transport of heat into the central Arctic Ocean. The Arctic Dipole pattern occurred in all summer months of 2007 and helped support the record 2007 summer reduction in sea ice extent (Overland et al., 2008). Overland et al., 2010 also found that the Arctic Dipole pattern tended to create an increase in easterly winds in the lower half of the atmosphere of 40% in fall, between 2002 - 2008. Fall 2008 through spring 2009 featured the old AO pattern. The new Arctic Dipole pattern re-appeared in June - July 2009, but the old AO pattern dominated in August - September, resulting in greater sea ice extent than in 2007 and 2008. The Arctic Dipole pattern was active again in October, inactive in November, and reasserted itself this December. As a result, Arctic sea ice reached a new record minimum for a 10-day period in early November, increased above record lows during late November and early December, and appears poised again to reach a new record minimum later this December (Figure 2).
Figure 2. Sea ice extent in the Arctic for this year (blue line) compared to the record low year of 2007 (green line) and 1979 - 2000 average (gray line). One could make the ice loss looks less significant by using the full satellite data record from 1979 - 2008 for the average. Image credit: National Snow and Ice Data Center.
Arctic Dipole blamed for colder winters in East Asia
It turns out that the new Arctic circulation patterns help to intensify the Siberian High, a large semi-permanent region of surface high pressure prevalent in winter over Siberia. According to Honda et al. (2009), this results in increased flow of cold air out of the Arctic in early winter over eastern Russia, Japan, Korea, and eastern China, causing colder temperatures. By late winter, the pattern shifts, resulting in colder than average temperatures from East Asia to Europe.
Arctic Dipole blamed for drier winters in Northern Europe
Francis et al. (2009) found that during 1979 - 2006, years that had unusually low summertime Arctic sea had a 10 - 20% reduction in the temperature difference between the Equator and North Pole. This resulted in a weaker jet stream with slower winds that lasted a full six months, through fall and winter. The weaker jet caused a weaker Aleutian Low and Icelandic Low during the winter, resulting in a more negative North Atlantic Oscillation--a pattern that usually brings reduced winter precipitation over Alaska and Northern Europe and increased precipitation over Southern Europe. A more negative NAO also tends to bring cold winters to eastern North America and Europe. Though it was not mentioned in the article, reduced Arctic sea ice may also cause dry early winter conditions in the U.S. and the Caribbean (Figure 3). The authors noted that strong La Niña or El Niño events can have a much larger influence on the wintertime atmospheric circulation, which will overshadow the changes due to Arctic sea ice loss.
Figure 3. Difference in early winter precipitation (November - January) between five years that had low Arctic sea ice (2005, 2006, 2007, 2008, and 2009), and five years that had unusually high Arctic sea ice extent (1981, 1984, 1986, 1989, 1993). Note that low sea ice may be responsible for dry conditions in early winter for the Caribbean and most of the U.S.
Commentary
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 feedback loop increases the likelihood that an ice-free Arctic in the summer will indeed come by 2030, as many Arctic experts are predicting. It's worth noting that such an atmospheric circulation shift was not predicted by the climate models. Indeed, the loss of Arctic sea ice over the past three years exceeds what any of our models were predicting (Figure 4). While we can rightly criticize these models for their inaccuracy, we should realize that they are just as capable of making errors not in our favor as they are of making errors in our favor.
Figure 4. Arctic sea ice extent from observations (thick orange line) and 13 model forecasts used to formulate the 2007 IPCC report (light lines). The thick black line is the multi-model ensemble mean, with the standard deviation plotted as a dashed black line. Image has been updated to include the observed 2008 and 2009 measurements. None of the models predicted the record 2007 sea ice loss. Image credit: Arctic sea ice decline: Faster than forecast by Stroeve et al., 2007.
References
Francis, J.A., W. Chan, D.J. Leathers, J.R. Miller, and D.E. Veron, 2009, "Winter Northern Hemisphere weather patterns remember summer Arctic sea-ice extent", Geophysical Research Letters, 36, L07503, doi:10.1029/2009GL037274.
Honda, M., J. Inoue, and S. Yamane, 2009. Influence of low Arctic sea - ice minima on anomalously cold Eurasian winters, Geophys. Res. Lett., 36, L08707, doi:10.1029/2008GL037079.
Overland, J. E., M. Wang, and S. Salo, 2008: The recent Arctic warm period, Tellus, 60A, 589.597.
Overland, J. E., and M. Wang, 2010: Large-scale atmospheric circulation changes associated with the recent loss of Arctic sea ice. Tellus, 62A, 1–9.
Richter-Menge, J., and J.E. Overland, Eds., 2009: Arctic Report Card 2009, http://www.arctic.noaa.gov/reportcard.
Simmonds, I., and K. Keay (2009), Extraordinary September Arctic sea ice reductions and their relationships with storm behavior over 1979.2008, Geophys. Res. Lett., 36, L19715, doi:10.1029/2009GL039810.
Wu, B., J. Wang, and J. E. Walsh, 2006: Dipole anomaly in the winter Arctic atmosphere and its association with sea ice motion. J. Climate, 19, 210-225.
Zhang, X., A. Sorteberg, J. Zhang, R. Gerdes, and J. C. Comiso (2008), Recent radical shifts of atmospheric circulations and rapid changes in Arctic climate system, Geophys. Res. Lett., 35, L22701, doi:10.1029/2008GL035607.
Jeff Masters
Reader Comments
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Whenever a person says 'The science is settled.' they are the ones who cannot be reasoned with.
After all their mind is made up.
Consequently, if you are a person who says 'The science is settled.' then the rest of us have no choice but to accept the likelyhood that you are a 'follower' of The Church of the IPCC/AGC. That does not necessarily make you a parishioner; but, you certainly are following the teachings. In fact it is almost like a cult.
Falsified data is okay because it came from on high. You believe it and that is that.
Hence you cannot be reasoned with. We must not attempt to confuse you with the facts, to do so makes us denialists, contrarians and ignorant.
If I am on your IGNORE list, please, please, keep me there, it keeps the bandwidth down. Additionally, I rather enjoy not having to be insulted with being called names like denialist or contrarian when I dispute what you and your fellow travelers are selling.
Mind-numbed followers who use the IGNORE feature to avoid the unpleasantness of opposing views are not the people I want to reach, it is the people who come here as lurkers, who have their Filter set to SHOW ALL so as not to miss any of the comments.
I actually have a war within when it comes to climate change.
On one hand, I am that planner-guy. I am prepared for a hurricane to show up tomorrow. I also look for ways to avert disaster in all things I do. I feel naked if I haven't made a complete backup of all data on computers at work and home.
On the other hand, my understanding of our rather limited global earth science data sets does not call for much excitement, in my opinion. I have confidence that today's climate is unique to the last 30 years, but little, if any, confidence that it would be deemed special if adequately compared to conditions before the launch of satellites. Additionally, uniqueness isn't alone the measure of an anthropogenic contribution. Some data sets give the impression that we should be warming right now as we continue to pull out of the little ice age, that at least some warming would be expected without any human contribution.
Lastly, just as many of you point to the manufactured doubt industry as reason to disregard data such as that I mention above, I am disgusted by the exploitation of human emotion by the manufactured fear industry. That exploitation of human emotion is not something many recognize as they watch their favorite news program or read their paper, though it is rife with it. Emotion has no place in this discussion whatsoever.
For example, it is emotion that makes one think that air travel is more dangerous than driving an auto, but logic and statistical study prove otherwise.
And the experiment may decide our fate ultimately.
The time for action is NOW. To wait is well,ignorant and foolish.
Damn the debate over trivial numbers. The house is on fire.
Break out da Hoses.
And both burn Hydrocarbons that release the remnants into our Atmosphere,..one day..again,folks will walk and Travel by Ship and other Means again.
And horses are a good thing.
We cant sustain how we do it today,..into the future.
To do so,damns Generations to a world already changed by US....
The 0600Z run shows a H with a central pressure of 1052MB, which is about 31.08". IF that is the case, you're looking at record lows across many parts of the US.
The 0000Z runs shows several rdiges of H pressure from 1024MB to 1032MB across almost all of the Canadian provinces, Greenland and most of the US, which seems a bit odd, but this El Nino cycle is MESSING with alot of territory..
All virga so far, magenta color moved over Macon around 0800 hrs but nothing has hit the ground since then. Temp then was 38*F, has risen to 40*F now. Dew point now is 22.9*F and humidity is only 50%. Rain bands are still south and SW of Macon.
Time to set the train set up around the Christmas tree, always my favorite job! My wife always wonders why it takes so long to get it set up. I have to make sure it is working properly before the grandchildren get here, don't I? :)
Nothing but Rain here in Cent Al
Do you remember the cold snap around December 22-December 24 in TX? Dallas-Ft Worth AP reached a record low of -1F, on the morning of December 24th, the first time it fell below zero since the 1950 era.
That's the kind of cold air mass your looking at IF the 0600Z runs pan out. Best thing to do is watch the Arctic ridge build into AK from Siberia, as that cold air will eventually slip down from AK, through Canada into the CONUS!
Patrap effectively told us, 'Don't pay any attention to the man behind the curtain.', when he wrote "Damn the debate over trivial numbers...". It does kind of fit though...Wizard of Oz and AGW...both fantasies.
How can a reasonable discussion ever occur with such a blind following of a hoax mantra?
The numbers are not trivial, they have been falsified. If anything they should be called 'FAKE NUMBERS" instead.
Anyway, great post, atmo.
L8R
The EPA's Carbon Bomb Fizzles -- The administration has given a skittish Congress another reason not to pass cap and trade.
Excerpt
" To use that law to regulate greenhouse gases, the EPA has to prove those gases are harmful to human health (thus, the endangerment finding). Put another way, it must provide "science" showing that a slightly warmer earth will cause Americans injury or death. "
Would it include the South East also?
Yes it would include almost the entire lower 48.
Weather map from 12-22-1989. Look familiar to the 0600Z computer run?
Man!!!I wish I knew more about the models and weather and such...that would be exciting to track...winter weather is my kind of thing
I think were gonna Have a Blizzard Rudolph..!
Or 20 years ago
I apologize, my bad! 1989!!
G'morning.
My son is on his way back to base and will be reunited with his wife and children for Christmas.
He will have to fly an airplane to get there.
I am not against all modern transportation; however, we need to find ways to help people get around without going to the pump quite as often. And that is what "they" are afraid of.
Of course we will need to develop effective energy sources (not-petroleum) as we move forward into the next 30, 50, and 100 years, for reasons of supply. My science bones, so far, cannot condone alarm and legislated "We are going to make energy more expensive" based on AGW, though.
And good mornin to you, too.
Just to note something as a nearly hairless animal living in SE LA (rather than as a met): Patrap, does it not seem like we are getting a lot more cold rain than usual for December? Seems like the usual MO for us is to get a relatively warm rainy day or two and then a cold front. 40s and 50s and raining is not our norm. Right?
I take it your Son is returning from Overseas's Duty Chicklit,..welcome Him home for me as well.
So sorry, December 22, 1989, NWS St Louis, MO Forecast Office. Comparing the 0600Z models to what that H looked like in 1989. IF this forecast pans out it's gonna be super cold!!
Yup..last one like this was 89,
and before this ones over,..I suspect we will get that Artic Plunge as the Polar Vortex slips down like in 89.
The pattern is similar to 1989..and that was a Bad,cold few miserable Days here.
Does not look familiar. That high pressure center was around 1056mb.
12/22/1989:
Wasnt enough of them here to do all the repairs.
I think we should build a monorail atop the the dividing wall on the interstate hyws and have electric car rentals at the exits...LOL...I would use it for sure
The 0600Z run shows a 1052MB High pressure area situated over MT.
Please see post 483...
Man I need to go look up what happened in 1989...LOL
As the high advects southward the pressure will lower. There's a difference between having a 1052mb high over Montana and a 1056mb high near northern Texas.
When we get this setup,..with the colder freeze Line down to the Mouth of the River..beware.
If the pattern remains locked ..it will occur downstream for many.
Yes, he is. I will tell him that, thanks.
He'll take a plane, but the Horses will be assembled to greet him.
And yes, IF, that scenario plays out, you may have a White Christmas..
I came in to see if any changes in the GFS for next week and from what I'm seeing it is going to be "Bone Chilling Cold" for us......
And I really hate it being that cold......
We will have all kinds of no water complaints due to frozen pips.....
"UGH"
Taco :0)
the ditches are full but nothing on the roads yet,hope it stays that way.cold rain today but 70s sunday and monday then more rain from calif.tuesday.enough of the el nino for 2009.we need a drying out period
the crawdads love it so should be a bumper crop soon
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