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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URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE GRAND FORKS ND
930 PM CST MON DEC 14 2009
...ANOTHER BOUT OF DANGEROUS WIND CHILLS FOR THE AREA...
.HAZARDOUS WIND CHILLS OF 25 BELOW TO AROUND 50 BELOW ZERO WILL
ENCOMPASS THE REGION TONIGHT. WEST NORTHWEST WINDS 10 TO 20 MPH
WILL COMBINE WITH SUBZERO TEMPERATURES TO CAUSE THESE COLD WIND
CHILL READINGS. HIGH PRESSURE WILL BUILD INTO THE NORTHERN PLAINS
TONIGHT...BRINGING CLEAR SKIES BY TUESDAY MORNING.
MNZ001-004-005-007-008-NDZ006>008-014>016-024-026>030-038-054-
151800-
/O.CON.KFGF.WC.W.0006.000000T0000Z-091215T1800Z/
WEST POLK-KITTSON-ROSEAU-WEST MARSHALL-EAST MARSHALL-TOWNER-
CAVALIER-PEMBINA-BENSON-RAMSEY-EASTERN WALSH COUNTY-EDDY-NELSON-
GRAND FORKS-GRIGGS-STEELE-TRAILL-BARNES-WESTERN WALSH COUNTY-
INCLUDING THE CITIES OF...CROOKSTON...EAST GRAND FORKS...
HALLOCK...ROSEAU...WARREN...NEWFOLDEN...CANDO...LANGDON...
CAVALIER...MADDOCK...LEEDS...DEVILS LAKE...GRAFTON...
NEW ROCKFORD...LAKOTA...GRAND FORKS...COOPERSTOWN...FINLEY...
MAYVILLE...VALLEY CITY...ADAMS
930 PM CST MON DEC 14 2009
...WIND CHILL WARNING REMAINS IN EFFECT UNTIL NOON CST TUESDAY...
A WIND CHILL WARNING REMAINS IN EFFECT UNTIL NOON CST TUESDAY.
* DANGEROUS WIND CHILLS WILL OCCUR UNTIL NOON CST TUESDAY.
* WIND CHILL VALUES WILL DROP TO 40 BELOW TO 50 BELOW ZERO.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A WIND CHILL WARNING MEANS THE COMBINATION OF VERY COLD AIR AND
WINDS WILL CREATE DANGEROUSLY LOW WIND CHILL VALUES. THIS WILL
RESULT IN FROST BITE AND LEAD TO HYPOTHERMIA OR DEATH IF
PRECAUTIONS ARE NOT TAKEN.
&&
Mean is bad.
Nice is good.
We can agree to disagree.
:)
This is what I like about this time of year.
Reconciliation, kindness and understanding are true hallmarks of the season. Now whether I can actually put those principles into into practice is less certain...more difficult. Like trying to take a twisted limb and straighten it out. It takes time and willingness, but after a while, every disagreement can somehow be resolved with a willingness on both sides. If you don't have that, then it's best to let that branch die.
IT NEVER STOPS haha...approaching 3 inches here
TornadoDude, I pray and hope you get to partake of the wintery weather coming! Dr J, my boss, will grant your request, to bring joy to your heart :0)!!
It includes me!
sounds good to me! haha :P I think I will have some snow next week. Highs in the 20's, lows in around ten. bound to snow sometime :P
slight chance, then new years looks intriguing, maybe ice
Don't worry, I am sure you'll have a nice snowstorm to close out 12-31-09, just a hunch!!
It looks promising, that would be great. haha
You will get your hearts desire, patience training is not any fun!!
It was 76F at 2PM today, awesome, gorgeous, fantastic December day!!
Now look:
Mostly Cloudy
39 °F
(4 °C) Humidity: 60 %
Wind Speed: N 18 G 24 MPH
Barometer: 30.15" (1020.7 mb)
Dewpoint: 26 °F (-3 °C)
Wind Chill: 30 °F (-1 °C)
Visibility: 10.00 mi
That is a nice 37F temperature drop!!
I think they call that a cold front :P yeah, it was 54 today, 24 for the high tomorrow
Now that is a cold front, TX Style!! It will be about 30-35F by 7AM!!
Hi Chicklit
If only most here could agree to disagree. That's the reason I stay out of these "discussions". There has been some good stuff, but too many coming out of the woodwork just to tell the other side how stupid they are. GW has joined my list of things I only discuss with close friends, along with religion and politics.
All to the left, or all to the right, and you end up walking in circles. It takes left and right to walk towards the destination. (My little bit of wisdom for the evening)
Nite all.
edit: Just got this little bit of wisdom too. Thought I would share it.
Tropical Disturbance Advisory Number 11
DEPRESSION, FORMER MICK, Category 1 (01F)
18:00 PM FST December 15 2009
========================================
At 6:00 AM UTC, Depression, Former Mick (999 hPa) located at 20.4S 178.9W has 10 minute sustained winds of 35 knots and is reported as moving southeast at 10 knots.
Gale-Force Winds
===================
100 NM from the center in sectors from northeast through east to south
60 NM from the center elsewhere
Low level circulation center is sheared over a degree from deep convection. Cyclone moving under low level northwest steering field into cooler sea surface temperatures
BASED ON 120NM SHEARED DIST FROM EDGE YIELDING A DT2.0.MET=2.0, PT=2.0.
FT BASED ON MET, THUS T2.0/2.5/W1.5/24HRS.
Global models agree on a forecast southeast track and weakening.
Forecast and Intensity
=========================
12 HRS: 21.8S 177.2W - 35 knots (DEPRESSION)
24 HRS: 23.6S 174.8W - 30 knots (DEPRESSION)
48 HRS: 29.8S 167.1W - 25 knots (DEPRESSION)
THIS IS THE FINAL TROPICAL CYCLONE ADVISORY FROM THE FIJI METEOROLOGICAL SERVICE
Tropical Cyclone Advice Number 33
SEVERE TROPICAL CYCLONE LAURENCE, CAT 3 (01U)
3:00 pm AWST December 15 2009
==========================================
At 6:00 AM UTC, Severe Tropical Cyclone Laurence (975 hPa) located at 14.4S 125.5E has 10 minute sustained winds of 70 knots with gusts of 100 knots. The cyclone is reported as moving southwest at 8 knots.
Hurricane Force Winds
=======================
15 NM from the center
Storm-Force Winds
=================
20 NM from the center
Gale-Force Winds
================
45 NM from the center
Dvorak Intensity: T4.5/4.5/1.5/24HRS
Severe Tropical Cyclone Laurence is a small but intense tropical cyclone moving southwest close to the Kimberley coast.
VERY DESTRUCTIVE WINDS with gusts to 185 kilometres per hour are being experienced on the coast close to the system centre and are expected to extend along the coast as far as Mitchell Plateau before the system weakens to Category 2 overnight. DESTRUCTIVE WINDS with gusts to 130 kilometres per hour are expected to extend southwest to Kuri Bay overnight.
GALES with gusts to 110 kilometres per hour may extend further along the coast, reaching as far as Cockatoo Island on Thursday morning and as far as Beagle Bay later on Thursday or Friday.
HEAVY RAIN is expected to continue over the north Kimberley region, extending into the western Kimberley overnight. Daily rainfall totals in excess of 100mm are possible near the coast with totals decreasing further inland.
Tropical Cyclone Watches/Warnings
==================================
A Cyclone WARNING continues for coastal areas from Kalumburu to Cockatoo Island, extending inland to include Drysdale River and Mt Barnett.
A Cyclone WATCH continues for coastal areas from Cockatoo Island to Beagle Bay.
Forecast and Intensity
========================
12 HRS: 15.3S 124.8E - 50 knots (CAT 2)
24 HRS: 16.0S 124.5E = 40 knots (CAT 1)
48 HRS: 17.1S 124.9E - 30 knots (Tropical Low)
72 HRS: 17.6S 123.9E - 20 knots (Tropical Low)
Additional Information
=======================
Laurence is a small but intense system, as demonstrated by the observations at Troughton Island earlier today, where a peak gust of 185 km/h was measured as the system went directly over the island. An eye has been evident on IR and VIS imagery during the day with its best presentation being at 0430Z. DT peaked at 6.0 but other images produced a DT of only 5.0 based on a Enum of 5.5 [B surround] with an elongated eye adjustment -0.5. The FT is set at 4.5 in agrement with the PAT. ADT is running a little on the weak side having failed to identify the eye signature.
The system is likely to weaken overnight due to the influence of land as it tracks almost parallel to the coast toward Kuri Bay. On Wednesday the system is likely to come under the influence of a mid-level trough to the west, leading to a more south to southeasterly track; which will take it further inland and continue the weakening trend.
Tropical Cyclone Bulletin Number THIRTY-ONE
WELL MARKED LOW PRESSURE AREA, FORMER WARD (BOB05-2009)
8:30 AM IST December 15 2009
=============================================
Subject Depression weakened into a well marked low pressure area over Sri Lanka.
At 3:00 AM UTC, Depression, Former Ward over north Sri Lanka weakened further and lay as a well marked low pressure area over Sri Lanka and neighborhood.
It is likely to move westwards and emerge into Gulf of Mannar during next 24 hrs. There is a probability of intensification of the system over the Gulf of Mannar. The system is under watch.
CONCERNING NEW ORLEANS RAINFALL...ABNORMALLY WET CONDITIONS OVER
THE PAST COUPLE OF WEEKS HAVE MADE THIS THE WETTEST DECEMBER ON
RECORD. AS OF 3AM...THE NEW ORLEANS AIRPORT HAS RECORDED 19.39
INCHES OF RAIN THIS MONTH. THAT IS A WHOPPING 14.45 INCHES HIGHER
THAN THE NORMAL TOTAL RAINFALL FOR DECEMBER. THE HIGH RAINFALL
TOTALS THIS MONTH HAVE ACTUALLY ALREADY PUSHED DECEMBER 2009 INTO
THE TOP 3 WETTEST MONTHS EVER RECORDED AT THE NEW ORLEANS AIRPORT.
THE ONLY WETTER MONTHS WERE NOVEMBER 1989 WITH 19.81 INCHES...AND
MAY 1995 WITH 21.18 INCHES. WITH ANOTHER 16 DAYS OF THE MONTH
LEFT...AND MORE RAINFALL FORECAST FOR TODAY...IT IS ENTIRELY
POSSIBLE THAT DECEMBER 2009 WILL GO DOWN AS THE WETTEST MONTH EVER
FOR THE NEW ORLEANS AIRPORT.
RECORDS FOR AUDUBON AND THE REST OF THE NEW ORLEANS AREA COULD NOT
BE COMPILED IN TIME TO INCLUDE THEM IN THIS DISCUSSION.
I dont doubt this one bit. Im only 45 minutes north west of NOLA and I swear it has rained everyday this month. We knew it would be a wet winter per El nino but this wet?? I had no idea.
Ike how has your area been?
Rain and more rain.
Most of the heavier rain has fallen north or west of where I live. Only 4-6 inches in December, where I live.
it helps katrina only lasted 36 hours
From NO,LA.....
THE FRONT WILL MOVE THROUGH THE AREA LATE THIS AFTERNOON AND INTO
TONIGHT. UNFORTUNATELY IT NOW LOOKS LIKE THE FRONT WILL STALL JUST
SOUTH OF THE COAST AND THEN MOVE BACK TOWARD THE NORTH BRINGING
ANOTHER CHANCE OF RAINFALL TO EXTREME SOUTHEAST LOUISIANA AND
COASTAL MISSISSIPPI THURSDAY AND THURSDAY NIGHT.
6Z GFS @ 66 hours....
Sounds good to me. I rather 4-6 inches then the mess we have.
Agree....20 inches in 2 weeks...OMG....terrible.
You really don't get it do you.
All I am doing is shining the light of truth on the article.
Had the article opened with ..."After ten years of floating in the ocean and being tracked by authorities, a huge iceberg identified as B17B has begun to break up into hundreds of smaller more difficult to track pieces." Then I wouldn't have taken issue with it.
Journalism is acutely aware that readers rarely read to the end of an article. We were taught to place the least important parts of any article at the very end because of that understanding.
The person who wrote that chose to place one of the most pertinent fact about the iceberg at the end. Why did they do that? Because leaving the information out of the article until the very end meant that they could make the story seem to be something it wasn't.
It's all about the 'Good news is no news' philosophy employed by the media.
Apparently even Awake was one of those people they talk about as not reading to the end of an article.
Don't blame me for understanding how journalism works.
At one point on Saturday night, Edmonton had the dubious distinction of being the coldest place on Earth. The record low temperature of -46 degrees was measured at the Edmonton International Airport. With the Wind Chill, it felt colder than -50. The city itself was a balmy -35 degrees before factoring the Wind Chill.
Edmonton's frigid temperature was exceeded by a station in Siberia where the lowest temperature measured on Saturday night was -48 degrees. Edmonton's -46 degrees was 2 degrees off the coldest temperature ever recorded for the Airport. Set back on January 26, 1972, the coldest temperature recorded is -48.3 degrees. Saturday also saw the coldest low ever recorded at the Airport in December. Friday, Saturday and Sunday nights also saw record low temperatures for Edmonton Airport.
Temperatures will continue to be frigid for the next couple of days before warming up mid-week. On Thursday, Edmonton is currently expected to reach a high of 2 degrees!
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