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
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Local Text Forecast for
Lake Worth, FL (33461)
Dec 13 Tonight
Partly cloudy. Areas of fog developing. Low 69F. Winds SSW at 5 to 10 mph.
Dec 14 Tomorrow
Areas of morning fog. A few passing clouds, otherwise generally sunny. High 83F. Winds ENE at 5 to 10 mph.
Dec 14 Tomorrow night
Mostly clear skies. Low 72F. Winds ESE at 5 to 10 mph.
Dec 15 Tuesday
Times of sun and clouds. Highs in the low 80s and lows in the upper 60s.
Dec 16 Wednesday
Some sun with a few showers possible. Highs in the low 80s and lows in the mid 60s.
Dec 17 Thursday
Scattered showers. Highs in the mid 70s and lows in the mid 60s.
Dec 18 Friday
Showers possible. Highs in the upper 70s and lows in the mid 60s.
Dec 19 Saturday
Scattered thunderstorms possible. Highs in the low 80s and lows in the mid 60s.
Dec 20 Sunday
Mostly Cloudy. Highs in the upper 70s and lows in the low 60s.
Dec 21 Monday
Cloudy. Highs in the mid 70s and lows in the low 60s.
Dec 22 Tuesday
Cloudy. Highs in the mid 70s and lows in the low 60s.
I'll take 5 LBS of salt in my wounds please!!
Early-warning radar
Cyclone Mick
Cyclone Mick
Link
By SETH BORENSTEIN, AP Science Writer Seth Borenstein, Ap Science Writer
2 hrs 28 mins ago
COPENHAGEN – As police cracked down on climate protesters, church bells tolled 350 times Sunday to impress on the U.N. global warming conference a number that is gaining a following, but is also awash in contradictions.
Conference negotiators went behind closed doors in talks to pin down an elusive new pact on climate, talks in which the figure 350 looms as a goal for true believers, but one that appears impossible based on progress so far.
It refers to 350 parts per million of carbon dioxide in the atmosphere, the highest concentration that some leading scientists say the world can handle without sparking dangerous climate effects.
"It's the most important number in the world," said Bill McKibben, founder of the environmental activist group 350.org. "It's the line between habitability on this planet and a really, really desolate future."
Not everyone buys into that. But an entire environmental group has sprung up around the number, pushing 350 as a goal, sporting it on T-shirts and flags waved by throngs of protesters that marched to the conference center over the weekend. About 100 nations at the U.N. climate summit have signed on to the idea of heading for 350.
Actually, the world has lived with more than 350 for a while.
The last time the Earth had 350 ppm of carbon dioxide in the air was a generation ago, in the fall of 1989. This year CO2 pushed over the 390 level. When scientists started measuring carbon dioxide in 1958 it was 315.
Since the atmosphere passed the 350 level, ice sheets have been melting and other dramatic changes have been happening. Prominent scientists — notably NASA's James Hansen, one of the earliest to warn about global warming, and Rajendra Pachauri, head of the Intergovernmental Panel on Climate Change — have said 350 is the only safe level of carbon dioxide in the air.
Still, many economists, political leaders, and even some scientists believe that the worst effects of global warming can be avoided even with less stringent actions.
But there is general agreement among negotiators and climate scientists that continued global warming will lead to dramatic changes that mean more widespread drought in some regions, greater flooding along coastlines, stronger storms and the loss of species.
On Sunday, hundreds of churches around the world had signed up to ring bells at 3:50 p.m. in their respective time zones
For the rest of the article click here.
Someone please send flowers! LOL!! Guess people are watching football?
Maybe people are upset because GFS stopped calling for Christmas snow in the S Plains and SE.
Indeed, the ridge is forecasted with certainty to head east and weaken while allowing cold fronts to swing on by starting Wednesday. In fact, by this weekend into Christmas week be prepared for an arctic outbreak my friends!!!
The main factor if you ask me attributing to these summer like temps is the location of the jet stream relative to south Florida.The core of the jet stream has extended from northern Mexico across the northern Gulf of Mexico to the mid-Atlantic and northeast United States. The location of the jet stream typically marks the approximate track of winter storm as they move from west to east across the nation. The southwest-to-northeast orientation of this jet stream across the Gulf coast is significant in that it prevents cold fronts and their associated cold air masses from penetrating too far south into Florida. As a result, recent cold fronts have either stalled right over south Florida or not made it this far south, keeping the region mainly on the warm side. Another contributing factor is an area of high pressure in the middle and upper levels of the atmosphere that has been nearly stationary over the Greater Antilles and Bahamas .The northern edge of the dome of high pressure area has extended far enough into south Florida to help keep cold fronts north of our region.
Although El Niño winters usually bring wetter and cooler than normal temperatures to south Florida, they are also marked by a stronger than normal southern jet stream.Till now the jet stream has stayed far enough to the north to keep the cooler and wetter weather just to our north. In fact, much of the southeast United States has been cooler and wetter than normal. Even within south Florida, slightly cooler and wetter conditions have been observed along the southwest Gulf coast and Lake Okeechobee region compared to southeast Florida as fronts have been able to barely clear those areas before stalling over southeast Florida. A slight shift in the jet stream pattern and an eastward retreat of the high pressure over the Greater Antilles and Bahamas is all that it would take to bring the cooler air masses down to south Florida. As the winter progresses, look for the possibility of these southward shifts in the jet stream pattern which could bring periods of wetter and cooler conditions forecast for this winter.
Adrian
Nope, I'm back like a bad penny!
Just got off the phone with my son in Hawaii...the 6 hour time diff. can be difficult to maneuver. Good news; they're moving back stateside, to SoCal, at the end of December. Whoo hoo, have JetBlue, will find webbernet's specials!
So did the Saints win? Seriously, I don't see it on the blog anywhere...pfft :)
Don't know where that forecast is from as most are forecasting big changes by the middle of next week into the rest of December. No more stalled fronts(which is anomalous for this time of year)! Plus some cold air will get you into the Christmas spirit by this weekend!!!
The fact that no model has back-off from this cold blast into Christmas week is another eye-opening promise!
Did anyone tell Floodman? :)
Hi Nana...the Saints and the Colts did win...and happy your son is moving a bit closer!
Opps, that was his post. meant to quote him.
Ya' gotta love Atmo. This is him giving us "layperson's terms." He just. can't. talk down far enough. for a few of us.
Shame on them! They should do like a Hallmark Presentation, "With Limited Commercial Interruption." Or take more care with the editing. We watched in on cable, last weekend, I think. My husband can't figure out what's wrong with the little rag doll on the Island of Misfit Toys, and now he's got me wondering too...amusing this has evidently been bothering him since childhood!
I wonder if it's that she's just missing Raggedy Andy?
After we solve this mystery, I'm sure CC/AGW will be easy!
OMG...look what they did...Rudolph The Red-Nosed Reindeer
Link
Is nothing sacred? Next it'll be Jersey Shore Rudlolph & Elves. The dumbing down of our youth, oh woe is me...
ROFL at Full Metal Jacket Elves...I don't think I can even link it and not get banned!
Geez, I can't believe this happened in Connecticut. They can generally drive in "weather" in New England.
Must have tourists from Virginia! (I'm so going to get it for this.) heehee
Saturday
Dec 19 Showers
Hi: 67° Lo: 56°
Showers. High 67F and low 56F. Winds NW at 14 mph.
Sunday
Dec 20 Mostly Sunny
Hi: 68° Lo: 54°
Mostly Sunny. High 68F and low 54F. Winds N at 14 mph.
Monday
Dec 21 Rain
Hi: 69° Lo: 49°
Rain. High 69F and low 49F. Winds E at 5 mph.
Tuesday
Dec 22 Showers
Hi: 69° Lo: 49°
Showers. High 69F and low 49F. Winds NW at 7 mph. Link
Looks like you need to talk to some folks in Norman, Oklahoma!(?)
wdtinc
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I see some posts from today on flooding in the "other" south (not Florida, lol). I need to find an overview somewhere...
Glad you said "Bing"
So...let's go with an ice storm instead!
As long as you stay out of the car--please!
Link
Only look at the 00Z and 12Z runs with the upper air and PIREPS incorporated into the model
(PIREPS-pilot reports)
I might be able to tell you, if he would stop writing in German. It drives me nutso...so of course I'm the perfect foil.
What the heck does does this mean, except for the English part...that even I get, lol.
Awake, was ist los? Ich habe schon geschrieben die Antwort. Sieh auf! Try refresh and look at my response!!!! It is practically impossible for one to ignore you. LOL
I think I would...
Does the Farmers' Almanac count?
We have very fuzzy caterpillars (missing their usual stripe, hmm, don't know what that's about),
tons of acorns,
squirrels look about normal to me, though...they're always chubby here.
Say Doug, did you read that Pensacola has the worst tap water in the nation? Got Britta or Pur filters?
Good night everyone, want to turn in at a semi-decent hour for a change. Have a great week, all!
Look who shows up after I go to hit the hay?
Way to diss a lady...or me :)
I know you had a great football day, have fun with the Blog, and I'll leave you the same message I left Geoff:
... check out 1063. Gro' was in top form today. He WU'ed us a bunch more of these. I'll forward to you tomorrow, or you can ask Gro' if you "see" him.
'night, Geoff. One thing about a hard freeze, at least the fleas are dead! :)
for pat 18z
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