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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You don't have a blog, Astro.
I recommend you start one as we need all the help we can get. Consider it public service!
Position (lat. 0N/long. 0E)
Sustained maximum surface wind speed (kmph)
12-12-2009/0230
9.5/84.5
75-85 gusting to 95
12-12-2009/0830
10.0/84.0
65-75 gusting to 95
12-12-2009/1430
10.5/83.5
65-75 gusting to 95
12-12-2009/2030
10.5/83.0
65-75 gusting to 105
13-12-2009/0230
11.0/82.5
65-75 gusting to 105
13-12-2009/0830
11.5/81.5
65-75 gusting to 105
13-12-2009/2030
11.5/80.5
55-65 gusting to 95
14-12-2009/0830
11.5/78.5
45-55 gusting to 65
---
this format will look poor however I just noticed the intensity looks very oddish
Cleo is now extremely large in size and disorganized, as I previously mentioned. It even extends to the equator, where it comes into contact with Ward's spiral band. Is David the name of the next S. Indian Ocean storm that could from?
I am planning on starting blog entries soon, mostly talking about the signs of climate change, Southern Ontario weather, and interesting weather phenomena or patterns worldwide. However, do not expect a regularly reliable blog in terms of timing, as I am often rather busy.
Is that for the middle of the Atlantic Ocean, or a tropical storm?
Had to read back and see why you were calling me a punk, only to found out you were actually referencing a comment PensacolaDoug made. :)
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Actually, he can access his settings etc through the MY QUICK MENU at the top of this page.
The programming must be set to identify a member as a blog only if they actually post something in their blog.
While astro might not be identified as a blog, he still can use the various menus to change various settings.
I love it when Ont gets snowed in :)
Except that not everybody gets snowed in. A friend of mine who lives a couple kilometres north of me says that their house has a door that opens inward so one can get out when they would otherwise be "snowed in". And don't forget that giant Victoria snowstorm that once brought 60 cm to the city!
Do you mean satellite? Cleo spans the whole region from 20S to the equator and from 65E to 80E. It has split into two circulations within the past 12 hours, with the southwest circulation looking like a shock wave (it was actually a large area of convection just a couple hours ago, and a looser convection has drifted north of 10S. The wave behind it might also interact both with the Australian system (when that storm affects the high pressure system west of Australia) and Cleo as well. Just 12 hours ago, Cleo was much more organised, with a clearly identifiable center and convection around it. Now it has completely expanded and split into two. Unusual behaviour was noted in the previous tropical cyclones, in the West Pacific, Nida (which exploded in size after weakening to a cat. 4 and creating a hole in the subtropical ridge) and TS 28W (which formed after combining the main convection of Nida and part of an ITCZ system from the equator, and then thowing out anotehr piece of circulation which twice formed and disappated near the Philippines, and is still located near the country). This may be having an effect, as I previously hypothesized, on global SSTs and storm tracks.
AOI
AOI
AOI
AOI
Humor in Comments
There were three other Davids also:
Hurricane David
Typhoon David
And there was also Tropical Cyclone David but I couldn't find any pics.
Similar behaviour has occured with ward, which rapidly organised itself from a wave to a strong tropical storm in less than 24 hours. More recently, an area of convection almost literally exploded, causing the storm to loop back on itself. After the convection started to weaken, a front-like feature to the northwest of the storm swung south, then back north toward a storm in Southern China, while the southwestern line of convection meets Cleo at the equator. Much of this progressed just in the last six hours. Link
The Australian system has organised itself in the past 24 hours, despite part of the system being on land. It was tracking in a generally WSW direction until something nudged it south in the past 12 hours, where at the coast it comes in contact with 32C warm water. Finally, there seems to be a tropical-looking wave organising near 10S, 172E, where water temperatures are near 29C and the system seems to be part of a front-like ICTZ pushing southeast toward the Humboldt. Link
Indian Ocean wind shear map
Australia wind shear map
SE Pacific wind shear map (165E to 135W)
ok
http://en.wikipedia.org/wiki/Bubonic_plague
Then I thought of this song, from the 1960's while I was growing up"
I have to stop wasting my time reading the peer-reviewed literature. I can just go to YouTube and find the father/son research posts.
Peterson, T.C., Assessment of urban versus rural in situ surface temperatures in the contiguous United States: No difference found, Journal of Climate, 16, 2941-2959, 2003.
One of several studies making the same conclusions.
Ironic you should mention that.
China seals off town amid plague outbreak
3rd death linked to infectious disease caused by Black Death bacteria
pneumonic plague
Nite all.
Hurricane David was the first storm I went though. Very interesting, got my attention.
Nothing to see here. All tidied up to fit the mold...
Don't leave out Zeppelin!
Also partial to the Who, Jackson Brown, and Floyd, myself.
Thank God for that! My wife, my mom and my daughters all had blonde/red/brunette mixed hair. Starts blonde and as those years creep by the brunette and red hair creep in! My daughter has dirty bolde hair, my son in law has blonde hair also! My dad, grand dad and dreat grandfather and myself have black hair.
I grew up with all the music from the late 50's through the late 70's. I am a classic rock or christian rock lover. No heavy metal, no rap either!!
PSST, hey you, 1970, see link below :0)!!!
Link
Here's some old, classic Motown music.
Martha Reeves and the Vandellas
Dancing in the Street
12/12 16:00
Temp:26.0C(78.8F)
Wind: 32km/h(19.9mph)
Gusts: 43km/h (26.7mph)
Pressure: 1004.0 hPa
Rain since 09:00: 114.8mm (4.5')
RADAR loop
I fell in love with weather at 7 yrs old. I grew up in the Northeast, so I enjoy all types of weather.
I now live in the southern end of Tornado Alley, in Arlington, TX. I have been here 29 yrs, so my favorite weather to follow is severe thunderstorms.
From March 1-June 1 each spring we have numerous severe thunderstorm warning and several tornado warnings for Dallas and Tarrant counties, the heart of our metro area.
I have seen 115MPH wind gusts, grapefruit sized hail, several funnel clouds which later became tornadoes. Whenever we have a surface Low nearby, we always seem to be in the "triple point". That is the warm sector, close to where the warm front, cold front and the surface Low meet.
You have SE surface winds, warm and very humid, SW wind shear and dry air being fed into a negatively tilted trough, with a cold front right behind the "dryline". The lift is enhanced and the wind shear causes explosive development of storms.
Every scenario is a new adventure! That will determine if the threat is strong straight line winds up to 80MPH, large hail and torrential rain or a large hail and tornado. Thankfully, it's usually the 1st two..
Tropical Cyclone Advice Number 9
TROPICAL LOW 01U
5:00 pm ACST December 12 2009
==========================================
At 3:30 pm CST [2:00 pm WST], Tropical Low (1002 hPa) is located at 13.0S 130.2E was estimated to be on the coast 100 kms southwest of Darwin and 410 kms east northeast of Kalumburu and moving southwest at 6 knots
The tropical low is expected to develop into a tropical cyclone early on Sunday as it moves into the Timor Sea.
GALES with gusts to 100 kilometres per hour are expected on the coast between Wyndham and Mitchell Plateau in Western Australia during Sunday afternoon or evening.
HEAVY RAIN is expected in the far north Kimberley region later on Sunday and may cause localised flooding.
Tropical Cyclone Watches/Warnings
=================================
A Cyclone WARNING has been declared for coastal areas from Mitchell Plateau to Wyndham, in western Australia.
A Cyclone WATCH is now current for coastal areas from Mitchell Plateau to Kuri Bay and from Wyndham to the Western Australia/Northern Territory Border.
Forecast and Intensity
=====================
12 HRS: 13.1S 129.0E - 35 knots (CAT 1)
24 HRS: 13.0S 128.1E - 50 knots (CAT 2)
48 HRS: 13.4S 127.2E - 65 knots (CAT 3)
72 HRS: 14.9S 125.8E - 50 knots (CAT 2)
Additional Information
======================
Tropical low 01U has tracked steadily southwest just inland of the western Top End coast and at 06Z was located by radar north of Daly River Mouth. The area of strongest winds measured on Doppler radar south of the low's centre has moved southwest from the Darwin area towards Channel Point. The low was assessed at Dvorak FT=MET=PAT=2.5 at 06Z and is forecast to move west into the Timor Sea, under the influence of a low-level ridge over the continent. The low is forecast to develop into a tropical cyclone early on Sunday, then intensify further in a favourable environment. The cyclone is expected turn south or southwest and approach the western Kimberley coast on Monday or Tuesday.
Here's conditions down on da bayou.
Just got home from work. Going to bed now. g'nite all.
CORRECTED TROPICAL CYCLONE ADVICE NUMBER 9
Issued by the BUREAU OF METEOROLOGY, DARWIN
at 5:00 pm CST [4:30 pm WDT] Saturday 12 December 2009
A Cyclone WARNING has been declared for coastal areas from Mitchell Plateau to
Wyndham, in western Australia.
A Cyclone WATCH is now current for coastal areas from Mitchell Plateau to Kuri
Bay and from Wyndham to the WA/NT Border.
At 3:30 pm CST [2:00 pm WST] a Tropical Low was estimated to be on the coast,
100 kilometres southwest of Darwin and 410 kilometres east northeast of
Kalumburu and moving southwest at 11 kilometres per hour.
The tropical low is expected to develop into a tropical cyclone early on Sunday
as it moves into the Timor Sea.
GALES with gusts to 100 kilometres per hour are expected on the coast between
Wyndham and Mitchell Plateau in Western Australia during Sunday afternoon or
evening.
HEAVY RAIN is expected in the far north Kimberley region later on Sunday and may
cause localised flooding.
FESA-State Emergency Service advises that there are no community alerts at
present. Communities between the Northern Territory border and Kuri Bay should
listen for the next advice.
Details of Tropical Low at 3:30 pm CST [2:00 pm WST]:
.Centre located near...... 13.0 degrees South 130.2 degrees East
.Location accuracy........ within 35 kilometres
.Recent movement.......... towards the southwest at 11 kilometres per hour
.Wind gusts near centre... 85 kilometres per hour, and intensifying
.Severity category........ below cyclone intensity
.Central pressure......... 1002 hectoPascals
The next advice will be issued by 8:00 pm CST Saturday 12 December [6:30 pm WST
Saturday 12 December].
Tropical Disturbance Summary
TROPICAL DEPRESSION 01F
18:00 FST December 12 2009
==================================
At 6:00 AM UTC, Tropical Depression 01 (999 hPa) located at 12.4S 174.6E is reported as moving southeast at 10 knots. Position FAIR based on multispectral infrared imagery with animation and peripheral observations. Sea surface temperature is around 29C. Organization has improved significantly with increase in convection in that last 24 hours. System lies under a 250 HPA trough in a moderately sheared environment. Outflow mainly to the north and east with dry air entrainment to the south. A surface ridge to the south directs a southeast surge and a monsoon northwest surge to the north. TD01F is steered by a northwest deep layer mean winds. Most global models are developing the system and moving it southeast into area of increased shear.
POTENTIAL FOR THIS SYSTEM TO DEVELOP INTO A TROPICAL CYCLONE IN THE NEXT 24 TO 48 HOURS IS MODERATE.
Just popped in for a quick look...
Am I reading that right, no posts for almost 3 hours?
Wonder what the record is on the blog for the longest time between posts?
Let's see if he can stay away when the first major is forming in the Atlantic in 2010.
One less person to fight with me:(
Morning Ike.
How come 456 is leaving?
Also, I caught something yesterday about Floodman being sick or something...
I hope he's ok. I like that hippie dude...
Link
Wasn't aware of Floodman..hope he's okay.
Too bad about 456. Always makes one a little sorry to see one of the family move on. Congratulations on his success and and the upcoming birth of his son though.
Hope you're doing well...
I'm fine...I've had people tell me that back surgery is rather risky. Some have told me they wish they hadn't had it.
I sell health insurance for a living...
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