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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For example, this excerpt was taken from: Arctic Sea-lce Extent and Anomalies, 1953-1984
Although no Siberian low is mentioned it is assumed that with such anomalous high pressure over the Beaufort/Chukchi Seas and low ice extent in that region of the Autumn of 1982 that the Arctic Dipole pattern was in place.
Ummm, he just answered the question...might be slanted observations going on a different way.
Really, read his post again!
6:31 PM GMT on December 11, 2009
Yes, the data is of poorer quality pre-1953. But was anyone sailing the Northwest Passage in ice-free waters at anytime between 1497 and 2005? No. Ships have been trying to do that for 500 years, and have not been able to until 2005. I think it is unlikely that there has been enough open water in the Arctic to trigger the Arctic Dipole pattern since at least the Medieval Warm Period of the 1300s.
Jeff Masters
fair enough...but if the NAO, AO, PDO, etc. caused very similar changes in the past, it seems reasonable that they are also responsible for the current changes and that we've just never noticed it before. also, wouldn't melting in the past documented in those articles also have induced the same phenomenon if the phenomenon is indeed an result of melting?
There was much more variability in arctic sea ice than shown in the seasonal image provided by "The Cryosphere Today" with especially low values of arctic sea ice in the early 1960's.
Oh, no more ice is needed. I'm sure Dr. Masters just had an LSD binge last night and wrote this blog entry under the influence. Thanks RitaEvac. I definitely feel better now that you've solved that pesky little ice melting issue.
But without satellite observations, human observation along the passage AND communication, and/or some dumb luck they would have needed to leave port at exactly the right time and then luck out on navigating a maze quickly to do it.
Pre and post satellite era obs in largely uninhabited (then and/or now) just isn't an apples to apples comparison.
This is such a weak spot in our observational record it lends only enough info for us to think it likely or unlikely, nothing more.
Hey Pat, how are you today? Still recovering from the storms?
On January 19, 1977, Old Man Winter paid an unwelcomed visit to residents of Miami, Florida (yes, Florida, not Ohio) and brought along a surprise gift -- snow! For the first time in the history of the extreme south of Florida, snow danced through the air and dusted the ground briefly. A quarter century later, the scene has not been repeated.
The same time as the cold southern US episodes mentioned by Oldmanwinter in post 62?
Thanks for this nugget of info, BTW.
I went to geology.com this time, but I know I've read about this elsewhere.
excerpt from Dr. Masters' post:
But was anyone sailing the Northwest Passage in ice-free waters at anytime between 1497 and 2005? No. Ships have been trying to do that for 500 years, and have not been able to until 2005. I think it is unlikely that there has been enough open water in the Arctic to trigger the Arctic Dipole pattern since at least the Medieval Warm Period of the 1300s.
excerpted from geology.com
Norwegian explorer, Roald Amundsen and crew were the first to cross the Northeast Passage entirely by sea in 1906. Although the crossing was an important "first" it had little economic value because the journey took three years and used waters that were too shallow for commercial shipping. The first single season trip through the passage was by Henry Larsen and crew in 1944. Again the route taken was not deep enough for commercial shipping.
First Deep Draft & Commercial Vessel Crossing
In 1957, three United States Coast Guard Cutters, Storis, Bramble and SPAR became the first ships to cross the Northwest Passage along a deep draft route. They covered the 4,500 miles of semi-charted water in 64 days.
The first ship capable of carrying significant cargo to traverse the Passage was the SS Manhattan, a specially reinforced supertanker, in 1969. It was accompanied by the John A Macdonald, a Canadian icebreaker. This trip was taken to test the Northwest Passage as an alternative to building the Alaska Pipeline. At that time it was determined that the Northwest Passage was not economical and the Alaska Pipeline was built.
Long but great read. You can see similarities unfolding this year.
I personally enjoy looking for the tough questions and asking them to see how far down the road of understanding we can comfortably travel with our available data...and to define that phase "comfort with our available data" for each individual dataset.
No personal issue with your posts, conclusions, etc. whatsoever.
Cheers!
Very interesting how all these key elements lead to snow in FLorida. Very Neat.
Has to be the "Perfect" combo
Actually, Antarctic sea ice has been tracking very near normal. Southern sea ice is different from northern, in that it is mostly seasonal - it forms and thaws every year. So, it "grows" dramatically during the southern winter, then mostly thaws away in summer. It is currently in its most rapid melt phase.
At the moment, and for at least half of the year, there is very little solid (unfractured) sea ice buttressing the ice shelves and sheets. The ice shelves do a good job of buttressing, until they collapse anyway, which seems to be happening with greater frequency there.
LMAO j/k :)
Which post are you referring to?
If you are referring to my comments regarding ice, then go to this site for a really simple explanation.
http://www.units.muohio.edu/dragonfly/snow/icefloat.shtml
I typed in 'Why ice floats' on the Google bar at it took me there.
Ratatouille helps him "cook."
27 June 2008 05:10 pm ET
Why would they state there is no significant connection between erupting volcanoes under the arctic ice cap and melting Ice? These were not just vents, they were volcanoes documented over the last 10 years in a small portion of a huge unexplored ridge. Just curious :)
Edited:)
j/k
6:59 PM GMT on December 11, 2009
The abstract from Overland, 2008, "The Recent Arctic Warm Period":
"Arctic winter, spring and autumn surface air temperature (SAT) anomalies and associated sea level pressure (SLP) fields have decidedly different spatial patterns at the beginning of the 21st century (2000–2007) compared to most of the 20th century; we suggest calling this recent interval the Arctic warm period. For example, spring melt date as measured at the North Pole Environmental Observatory (2002–2007) is 7 d earlier than the records from the Russian North Pole stations (1937–1987) and statistically different at the 0.05 level. The 20th century was dominated by the two main climate patterns, the Arctic Oscillation/Northern Annular Mode (AO/NAM) and the Pacific North American-like (PNA*) pattern. The predominately zonal winds associated with the positive phases of these patterns contribute to warm anomalies in the Arctic primarily over their respective Eastern and Western Hemisphere land areas, as in 1989–1995 and 1977–1987. In contrast, SAT in winter (DJF) and spring (MAM) for 2000–2007 show an Arctic-wide SAT anomaly of greater than +1.0°C and regional hot spots over the central Arctic of greater than +3.0°C. Unlike the AO and PNA*, anomalous geostrophic winds for 2000–2007 often tended to blow toward the central Arctic, a meridional wind circulation pattern. In spring 2000–2005, these winds were from the Bering Sea toward the North Pole, whereas in 2006–2007 they were mostly from the eastern Barents Sea. A meridional pattern was also seen in the late 1930s with anomalous winter (DJFM) SAT, at Spitzbergen, of greater than +4°C. Both periods suggest natural atmospheric advective contributions to the hot spots with regional loss of sea ice. Recent warm SAT anomalies in autumn are consistent with climate model projections in response to summer reductions in sea ice extent. The recent dramatic loss of Arctic sea ice appears to be due to a combination of a global warming signal and fortuitous phasing of intrinsic climate patterns".
So Dr. Overland is saying that the Arctic Dipole pattern of the 2000s are unique in the past century. At a talk at AGU of his that I saw last year, he commented on the warm period in the 1930s and 1940s in the Arctic, which also had the unusual meridional (south to north) flow of air into the Arctic. This flow was due to an unusually persistent and strong NAO pattern that set up in the 1930s that was unique and distinct from the Arctic Dipole pattern we are seeing in the 2000s, he said.
Note also in the abstract above that "fortuitous phasing of intrinsic climate patterns" is partially to blame for the recent Arctic sea ice loss. We wouldn't be where we are not without a strong natural AO pattern that set up in the early 1990s that brought strong winds that flushed a ton of ice out of the Arctic through Fram Straight between Greenland and Iceland. I've discussed this in previous posts, which I've summarized in my Sea Ice page on the climate change section of the web site.
Jeff Masters
Phew, thanks, really. I just wrote Dr. Jeff saying I knew I was prob. the least-bright bulb in the blog...but whassup wid dis? Okay, I did NOT say whassup, it's not appropriate for women of a certain age :)
From Sully's link, this plot from the Journal of Physical Oceanography shows a monthly mean (on left) from the entire year to vary relative to the 25 month mean by about the same amount. The summer lately does seem to have far more variability than what was found in the 25 year study for the 50s and 60s. The plot on the right is a 24 month running mean, a 2-year period that only shows a ~0.55 [edit, oops, typo] million square km extent variability.
However, THIS REPORT DOES HAVE SOME MISSING DATA where some interpolation in time and space has been carried out, particularly "there were no data for the Siberian sector during several years in the 1950s".
Physics Group Splinters Over Global Warming Review
As the science scandal known as ClimateGate grows, the largest U.S. physicists' association is finding itself roiled by internal dissent and allegations of conflict of interest over a forthcoming review of its position statement on man-made global warming.
The scientist who will head the American Physical Society's review of its 2007 statement calling for immediate reductions of carbon dioxide is Princeton's Robert Socolow, a prominent supporter of the link between CO2 and global warming who has warned of possible "catastrophic consequences" of climate change.
Socolow's research institute at Princeton has received well over $20 million in grants dealing with climate change and carbon reduction, plus an additional $2 million a year from BP and still more from the federal government. In an interview published by Princeton's public relations office, Socolow called CO2 a "climate problem" that governments need to address.
"It is Socolow whose entire research funding stream, well over a million dollars a year, depends on continued alarm over global warming," says William Happer, a fellow Princeton University professor and head of the Happer physics lab who has raised the question of a conflict of interest. The reason: the ostensibly neutral person charged with evaluating a statement endorsing man-made global warming is a leading proponent of precisely that theory whose funding is tied to that theory.
[end excerpt]
So if Exxon funded anti-AGW research and that somehow tainted such, then does BP providing funding for AGW research, when it is calling for carbon credit trading systems that by some estimates will be worth trillions by 2020, in turn taint AGW research in the same manner? There is a pretty clear conflict of interest in having a researcher beholden to AGW interests conducting a 'neutral' review of a societies' position on AGW.
Yes, BarryW., I noticed "northeast" after posting and did add a * when I WU'ed Dr. Jeff.
And I think you are most probably correct on your second point, icebreaking technology.
I'm just being a literal OCD arse, maybe.
Good afternoon everyone!
Hey, there, slacker (j/k)
I have to go, and I'm sure the blog will be happy for someone to change it up!
Rock on...
Thanks, I think. Love the company, lol.
hey, good time to come on the blog, some really informative posts today, I am learning more now then I have all year in my EAS classes
I'm learning that maybe I should just stick with the comics section of the paper. ;)
“It will without doubt have come to your Lordship’s knowledge that a considerable change of climate, inexplicable at present to us, must have taken place in the Circumpolar Regions, by which the severity of the cold that has for centuries past enclosed the seas in the high northern latitudes in an impenetrable barrier of ice has been during the last two years, greatly abated….
(see additional*)
….. this affords ample proof that new sources of warmth have been opened and give us leave to hope that the Arctic Seas may at this time be more accessible than they have been for centuries past, and that discoveries may now be made in them not only interesting to the advancement of science but also to the future intercourse of mankind and the commerce of distant nations.” A request was made for the Royal Society to assemble an expedition to go and investigate.
President of the Royal Society, London, to the Admiralty, 20th November, 1817, Minutes of Council, Volume 8. pp.149-153, Royal Society, London. 20th November, 1817.
OH Stop, no don't, because I need someone else here who is er, um, challenged(?) (j/k)
How those Gnagy art lessons coming? Did I spell that right -- and THANK YOU for posting that last night, I bust out laughing. You punched a hole in a, what shall we say, a ballooning "artiste"?
LoL, I am doing the experiment on the stove with two pots full of ice and water right now. One being influenced by ambient temperature and the other with the burner :) J/K L8R
LOL youre on a roll today
Yes, but could it be done during the "Medieval Warm Period of the 1300", the guess is yes. So is it a man made phenomena... or a Global warming cycle.. thats the 64 dollar question.
No one disagrees its happening... where the disagreement comes in to the equation, is... what is causing it.
LOL the milk keeps on coming out my nose :P jk
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