# Wobbles in the Barriers: Arctic Oscillation (4)

By: Dr. Ricky Rood , 4:22 PM GMT on October 14, 2013

Wobbles in the Barriers: Arctic Oscillation (4)

This is a continuation of my series on the Arctic Oscillation / North Atlantic Oscillation. Links to background material and previous entries are at the end.

In the last entry I suggested that if you were on a bridge overlooking a swiftly flowing creek then you would notice that twigs floating in the water did not move across the current. They are carried downstream along the edge of the current. The purpose of that comparison was to demonstrate how fast-moving, concentrated flows have the effect of isolating one side of the creek from the other. This is true in the creek, and it is also true about jet streams in the atmosphere.

One way to understand the Arctic Oscillation is to think of it as the variation of an atmospheric jet stream. For the Arctic Oscillation the jet stream of interest is the southern edge of vortex of air that circulates around the North Pole (see previous entry). Air inside the vortex often has characteristics different from air outside it. Intuitively for the Arctic, there is colder air on the side toward the pole. If you look at trace gases, like ozone, they are different across the edge of the vortex. The takeaway idea is that the edge of the vortex is a barrier. It’s not a perfect barrier, but the air on one side is largely separated from the air on the other side. In this blog, I describe the difference between a strong and a weak vortex – which is the same as the difference between the positive and negative phases of the Arctic Oscillation and the North Atlantic Oscillation.

Figure 1: This figure is from the point of view of someone looking down from above at the North Pole (NP). Compare this perspective to Figure 1 in previous blog. This represents a strong, circular vortex centered over the pole, which encloses cold air, represented as blue. The line surrounding the cold air is the jet stream or the edge of the vortex.

Figure 1 shows an idealized schematic of the North Pole as viewed from above. This is the strong vortex case, when there is exceptionally low pressure at the pole. Low pressure is associated with counterclockwise rotation in the Northern Hemisphere. This direction of rotation is called cyclonic. This strong vortex case is the positive phase of the Arctic Oscillation. During this phase, the vortex aligns strongly with the rotation of the Earth, and there are relatively few wobbles of the edge of the vortex – the jet stream. I drew on the figure two points, X and Y. In this case, the point X is hot and the point Y is cold. It is during this phase when it is relatively warm and moist over, for example, the eastern seaboard of the United States.

Figure 2 compares a strong vortex and a weak vortex. In both cases, the circulation around a central point is counterclockwise or cyclonic. However, in the weak vortex case, the vortex does not align as strongly with the rotation of the Earth and there are places where the edge of vortex extends southwards. The vortex appears displaced from the pole; it is not centered over the pole.

Figure 2: Examples of a strong, circular vortex and a weak, more wavy vortex. See text for a more complete description.

Whether the vortex is stronger or weaker is determined by the atmospheric pressure at the pole. In the winter, an important factor that determines the circulation is the cooling that occurs at polar latitudes during the polar night.

What determines the waviness or wobbles at the edge of this vortex? The structure at the edge of vortex is strongly influenced by several factors. These factors include the structure of the high-pressure centers that are over the oceans and continents to the south of jet stream. One could easily imagine a strong high-pressure center over, for example, Iceland, pushing northward at the edge of the vortex. This might push a lobe of air characteristic of the middle latitude Atlantic Ocean northward. Since the edge of the vortex is something of a barrier, this high-pressure system would distort the edge of the vortex and, perhaps, push the vortex off the pole. This would appear as a displacement of the vortex and its cold air over, for example, Russia. If the high grew and faded, then this would appear as wobbles of the vortex.

Other factors that influence the waviness at the edge of the vortex are the mountain ranges and the thermal contrast between the continents and the oceans. The impact of mountains is easy to understand. Returning to the creek comparison used above, the mountains are like a boulder in the stream. The water bulges around and over the boulder; the air in the atmosphere bulges around and over the mountain ranges. The Rocky Mountains in the western half of North America are perfect examples of where there are often wobbles in the atmospheric jet stream.

Figure 3: This figure is from the point of view of someone looking down from above at the North Pole (NP). This represents a weak, wavy, wobbly vortex displaced from the pole. The vortex encloses cold air, represented as blue. The line surrounding the cold air is the jet stream or the edge of the vortex. (definition of vortex)

Figure 3 shows an idealized schematic of the North Pole as viewed from above. This is the weak vortex case, when the low pressure at the pole is not as low as average and the pressure is much higher than the strong vortex case of Figure 1. This weak vortex case is the negative phase of the Arctic Oscillation. During this phase, the alignment of the vortex with the rotation of the Earth is less prominent, and there are wobbles of the edge of the vortex – the jet stream. In this case, the point X is cold and the point Y is hot. It is during this phase where it is relatively cool and dry (but potentially snowy) over, for example, the eastern part of the United States.

These figures help to explain the prominent signal of the Arctic Oscillation discussed in the earlier entries (specifically, this blog). That is, when the vortex is weak and wobbly, then there are excursions of colder air to the south and warmer air to the north. This appears as waviness and is an important pattern of variability - warm, cold, warm, cold.

The impact of the changes in the structure of edge of the vortex does not end with these persistent periods of regional warm and cold spells. The edge of the vortex or the jet stream is also important for steering storms. Minimally, therefore, these changes in the edge of the vortex are expected to change the characteristics of how storms move. Simply, if the edge of the vortex has large northward and southward extensions, then storms take a longer time to move, for example, across the United States from the Pacific to the Atlantic Oceans. In the positive phase of the Arctic Oscillation they just whip across. In the negative phase, the storms wander around a bit. A more complete discussion of this aspect of the role of the Arctic Oscillation will be in the next entry. (Note use of dramatic tension and the cliffhanger strategy of the serial.)

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Previous entries:

Barriers in the Atmosphere
Behavior
Definitions and Some Background

August Arctic Oscillation presentation

CPC Climate Glossary “The Arctic Oscillation is a pattern in which atmospheric pressure at polar and middle latitudes fluctuates between negative and positive phases.”

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

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##### 357. Patrap
 If the pause don't fit, you must acquit.
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##### 352. Daisyworld
 Quoting 349. tramp96:Science is founded on uncertainty. Each time we learn something new and surprising, the astonishment comes with the realization that we were wrong before. %u2014 Lewis ThomasQuick note: If you're going to quote Lewis Thomas, you should know more about the person, including many of his other quotes:"The central task of science is to arrive, stage by stage, at a clearer comprehension of nature, but this does not at all mean, as it is sometimes claimed to mean, a search for mastery over nature.""We habitually engage in meddling with nature. Until this century most of this meddling was good. Witness the preservation of the European countryside. But since then we've smoked it up and littered it and dumped too much in too many waters. I don't think it's our privilege to behave this way.""We're as clever as we think we are, but we'll be a lot cleverer when we learn to use not just one brain but to pool huge numbers of brains. We're at a level technologically where we can share information and think collectively about our problems. We do it in science all the time..."
##### 351. Daisyworld
 Quoting 348. Patrap:Seems they skipped the part where he went to Nam and served way before most were born.And a Year playing "Call Of Duty" on X box, does not count as "Service".Murica' Woo!I guess that to conservative ideologues, military service is only honorable when they deem it to be so. Just ask the Swift Boat Veterans for Truth.
##### 348. Patrap
 Seems they skipped the part where he went to Nam and served way before most were born.And a Year playing "Call Of Duty" on X box, does not count as "Service".Murica' Woo!
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##### 347. Neapolitan
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##### 346. Xulonn
 Quoting 338. iceagecoming:I think Al Gore is a hypocriteSheesh, I know I'm verbose, but that comment was a monster piece of silly claptrap. However, I was able to condense your "monster" comment into 7 words.Do you have a crush on Mr. Gore that makes you pay so much attention to him? Do you feel good - perhaps even giddy - when you hit the Enter key after such a composition? And why on earth would you post such claptrap in the comments section of a climate science blog?Most of the people here who are capable of critical thinking and understanding science very rarely mention his name - except to respond to climate denialists who are enthralled and captivated by him. And of course, as any intelligent and informed person knows, Al Gore is not a climate scientist. His hypocrisy does not have any impact - or even influence - on the settled science of AGW/CC.
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##### 343. Xulonn
 Quoting 341. Daisyworld:Yoboi's fallacy of logic: Quoting out of contextProof:Yoboi's chosen text from Xulonn to champion:"Bottom line, simply because something is peer-reviewed does not mean that it is infallible."The ACTUAL quote from Xulonn:"Bottom line, simply because something is peer-reviewed does not mean that it is infallible - but the 'respectable' traditional academic journals seek to both refuse bad science, and in the rare instance that bad science gets by peer-review process and is exposed - they purge the paper from their archives and acknowledged the errors."Conclusion:Yoboi has chosen to lie from now on by quoting out of context.Thanks Daisy. I've got grand master denialist Yoboi on ignore, but I guess those of you who still see his denialist b.s. should have the rest of my comment at the ready to counter his latest cut and paste claptrap. When I fully realized that he never applied critical thinking, and was simply lying about his desire to learn about the hard science that supports AGW/CC, I just gave up on him and used the ignore feature. I think the concept of scientific uncertainty and the use of error ranges, and the lack of application and use of the concepts of absolute certainty and "proof" is beyond the ability of most denialists to comprehend. I don't mean that as an insult, but rather as an observation. The academic peer review process is vastly superior to the lack of any critical review and quality standards practiced by the denialist community. To paraphrase an old saying, "The price of scientific truth and reality is academic rigor and eternal vigilance." Although denialists and charlatans jump on every sign of self-criticism and awareness in the scientific community, and of a lack of perfection in human endeavors as a sign of weakness, hard evidence and truth are on our side. As with AGW/CC itself, the ignorati would see even a 99% confidence levels in rigorous academic peer-review as an indicator of failure, while e=their <1% accuracies are seen as absolute proof of their perspective. Pathetic!
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##### 342. JohnLonergan
 Australia’s Bushfire Season Turns Sydney’s Skies OrangeAustralia has been enduring its hottest year on record, and the warm temperatures combined with dry conditions have sent wildfires whipping across the southeastern Australian state of New South Wales. The fires — some of the worst in a decade — have caused a deep haze to descend over Sydney and spurred the deployment of hundreds of firefighters across the region.More >>
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##### 341. Daisyworld
 Quoting 340. yoboi:[...]I will remind some people of that from now on...Yoboi's fallacy of logic: Quoting out of contextProof:Yoboi's chosen text from Xulonn to champion:"Bottom line, simply because something is peer-reviewed does not mean that it is infallible."The ACTUAL quote from Xulonn:"Bottom line, simply because something is peer-reviewed does not mean that it is infallible - but the 'respectable' traditional academic journals seek to both refuse bad science, and in the rare instance that bad science gets by peer-review process and is exposed - they purge the paper from their archives and acknowledged the errors."Conclusion:Yoboi has chosen to lie from now on by quoting out of context.
##### 339. Xulonn
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##### 337. JohnLonergan
 From the Vancouver Sun:Canada’s efforts accelerate a global tragedy of the climate commonsStephen Harper’s statement that Canada “won’t take ‘no’ for an answer” regarding the impending U.S. decision about the Keystone XL pipeline overlaps inauspiciously with a new study in Nature this week, which projects that, within a generation, known climates in most regions of the globe will be a “thing of the past”.University of Hawaii ecologist Camilo Mora and his co-authors project that the recent increase in extreme weather events is merely the prelude to the next half century’s “unabated heat wave” as, under a business-as-usual scenario, climate moves wholly outside its range of historical precedence. Wholesale climate shifts will occur soonest in the tropics, where most of the world’s population and much of its biodiversity live. The punchline? Says Mora, “any progress to slow ongoing climate change will require a larger commitment from developed countries to reduce emissions.” Yet Canada’s Prime Minister is leading the charge instead to accelerate carbon emissions from oilsands.Read more...
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##### 336. JohnLonergan
 Quoting 333. Birthmark:That was my (layman's) conclusion after quickly perusing the paper. Stoat's comment sums it up nicely, imo: "If you look through the paper to find the core substance, you won’t. There are layers of mush and piles of words but precious little hard matter. "That was precisely my experience with W&C(2013).If you want a laugh, read this destruction in the comments on Curry's own blog, almost Stoat level snark.http://judithcurry.com/2013/10/10/the-stadium-wav e/#comment-396495
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##### 334. georgevandenberghe
 Quoting 312. goosegirl1:re:301Here we go again... one year does not a climate make. A lot of slick graphics fool no one who can look up the climate trends. And- did you know that there is a whole big world out there? Not just the US? What about the flooding in Alberta, and in Colorado for that matter? Drought in New Zealand? Heat in Australia? LinkBut I do think we should avoid using extreme weather incidents(other than long term statistics of such which are significant) to bolster the already solid arguments that AGW is a sad reality.
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##### 332. georgevandenberghe
 Quoting 307. Patrap:Never, bring a hacksaw to a logging match.Actually I like "never bring a weather argumentto a climate fight".
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##### 331. JohnLonergan
 From Open Mind:The ICP reportMany of you are probably aware of a “report” which is intended to contradict the IPCC (Intergovernmental Panel on Climate Change) report. Its authors call it the “NIPCC” report for “Non-governmental International Panel on Climate Change.” It’s supposed to represent the very best that so-called “skeptics” have to offer.But in my opinion, a much more accurate acronym would be “ICP” report — for “Intentional Cherry-Picking.” You don’t have to look any further than their “Summary for Policymakers” (SPM) to see cherry-picking taken to the extreme. And I do mean, extreme. One of the most obvious, most egregious, and frankly most ridiculous examples is Figure 4 from their SPM. It looks like this:Here’s what they have to say when referring to this figure:“… a wide variety of datasets other than the HadCRUT global air temperature curve favored by the IPCC do not exhibit a warming trend during the second half of the twentieth century. See Figure 4.”Let’s find out whether or not their claim is correct. ...Grab some popcorn and watch the carnage ensue.
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##### 330. JohnLonergan
 All you need to know about Wyatt and Curry in two images:image sourceCompare PDO shown below with the figure above:Image and more at Eli RabbetIt looks like Wyatt and Curry is basically an exercise in mathturbation.
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##### 328. Patrap
 Climate Nirvana ?Maldives, a Nation of Islands in Peril from Sea Level Rise
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##### 327. BaltimoreBrian
 Quoting 276. yoboi:Dr Spencer debunked that.....
##### 326. BaltimoreBrian
 Quoting 324. Birthmark:New Study Discovers that the US is only a small portion of the Earth's Surface!Youse guys!
##### 325. Daisyworld
 Quoting 318. JohnLonergan:Yeah, I wanted to see the list, find out who my sock Puppet is.I wish I had a sockpuppet. I've always worked solo.
##### 323. FLwolverine
 Quoting 322. Naga5000:Oh it's no offense to you at all, I'm actually kind of flattered that we have reached "conspiracy sock puppet status" on the blog. I think that means we are doing something right. Don't worry, John, we all ready knew about your other handle "Birthmark" ;)I just wish you would give me a little more notice on the uniform of the day. Black & orange for the rest of the month?
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##### 322. Naga5000
 Quoting 320. FLwolverine:What? You don't want to be a fearsome, snow loving carnivore and the mascot of the Harvard of the Midwest?Edited to add: Also cuddly!Oh it's no offense to you at all, I'm actually kind of flattered that we have reached "conspiracy sock puppet status" on the blog. I think that means we are doing something right. Quoting 318. JohnLonergan:Yeah, I wanted to see the list, find out who my sock Puppet is.Don't worry, John, we all ready knew about your other handle "Birthmark" ;)
##### 321. Daisyworld
 Quoting 296. FLwolverine:#213 - Daisyworld, I've been meaning to thank you for that video. It's a good explanation. I'll bet Alley is a very interesting teacher.He's a very interesting scientist, overall. I got to see him in person at a meeting of the American Geophysical Union. The clip I provided ncstorm was part of a larger series, Earth: The Operators Manual. A very good series, if you have the time to watch.
##### 320. FLwolverine
 Quoting 316. Naga5000:Nah, I've had enough of the multiple handle nonsense. Today I was accused of being FLWolverine, before it was Neapolitan. MisterPerfect is no CEastwood, he's just misguided, most likely from reading Climate Depot articles. That's enough to drive any man crazy.What? You don't want to be a fearsome, snow loving carnivore and the mascot of the Harvard of the Midwest?Edited to add: Also cuddly!
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##### 319. Patrap
 If one would like a great story of climate change, step up and do a Thesis on the Maldives as they are the ones being impacted now.They need to move residents now, and have.Its a social and dynamic situation that layer the rising water, tenfold.It would do them and the World a great service.Think about it.After all, we have the gift to think, create, Build, but also destroy and make War like a fine Art.The World needs it young minds as never before.Time is not on yer side.We need to break the cycle, or the cycle will break us..without hesitation, or thought, let alone care.Published on Apr 9, 2012DemocracyNow.org - In part two of our interview with ousted president of the Maldives, Mohamed Nasheed, he describes the battle for democracy in his country after he was forced out at gunpoint in February. To his surprise, the United States instantly recognized the man who took his place, former dictator Maumoon Abdul Gayoom. Nasheed was a longtime pro-democracy activist who was jailed for six years under Gayoom's rule. The coup became news across the globe in part because Nasheed has become an internationally recognized leader in the effort to address the root causes of climate change. The Maldives rise just 1.3 meters above sea level, making his nation and other island states extremely vulnerable from rising sea waters due to global warming. We also speak with Jon Shenk, director of a new documentary about Nasheed's life, "The Island President," which is now playing in theaters. To watch the complete independent, weekday news hour, read the transcript and download the podcast, please visit http://www.democracynow.org
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##### 318. JohnLonergan
 Quoting 316. Naga5000:Nah, I've had enough of the multiple handle nonsense. Today I was accused of being FLWolverine, before it was Neapolitan. MisterPerfect is no CEastwood, he's just misguided, most likely from reading Climate Depot articles. That's enough to drive any man crazy.Yeah, I wanted to see the list, find out who my sock Puppet is.
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##### 317. BaltimoreBrian
 MisterPerfect and NRAamy both bragged on Aaron's blog about all the other handles they have. I think they made a lot of the troll handles here. If you google their handles and look back at their old comments it's obvious they're both racist psychos.
##### 316. Naga5000
 Quoting 314. JohnLonergan:I thought Eastwood and Perfect were one and the same.Nah, I've had enough of the multiple handle nonsense. Today I was accused of being FLWolverine, before it was Neapolitan. MisterPerfect is no CEastwood, he's just misguided, most likely from reading Climate Depot articles. That's enough to drive any man crazy.
##### 314. JohnLonergan
 Quoting 313. Naga5000:No one ever mentions Gore here other than you and CEastwood. We really don't care.I thought Eastwood and Perfect were one and the same.
Member Since: December 31, 1969 Posts: Comments:
##### 313. Naga5000
 Quoting 311. MisterPerfect:Al Gore IS propaganda.No one ever mentions Gore here other than you and CEastwood. We really don't care. We discuss the actual science behind AGW, and tend to post published papers on the subject, none of which study Al Gore.The first article, despite being from the bought and paid for "Climate Depot" doesn't even have anything to do with global climate. However, to the untrained eye, I'm sure it looks like he just "beat" AGW.
##### 312. goosegirl1
 re:301Here we go again... one year does not a climate make. A lot of slick graphics fool no one who can look up the climate trends. And- did you know that there is a whole big world out there? Not just the US? What about the flooding in Alberta, and in Colorado for that matter? Drought in New Zealand? Heat in Australia? Link
##### 310. MisterPerfect
 ^^ haha!still tickin'!Stick to the stints..cheap and effectivebe well P.P.
##### 309. Patrap
 I roll with NOAA and the er, Published stuff.It keeps Sen. Inhofe well, rubbed.I hope the man does well after his Bypass.Womp,wahhhhhhhhhhhhhhhhhhYa know, Bypass surgery is usually jus a money making scheme.I mean, who needs Surgeons and all dat medically stuff,really?
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##### 308. MisterPerfect
 Quoting 303. BaltimoreBrian:Mister aint perfect. ClimateDepot is a well known hack site that only denier sheep takes seriously.You have to be a complete crackpot to believe that Newton and Einstein are wrong about gravity.And sourcewatch.org is owned by the Center for Media and DemocracyCMD was founded in 1993 by environmentalist writer and political activist John Stauber in Madison, Wisconsin. Lisa Graves has served as executive director since 2009.[1][5] Graves previously worked for the Senate Judiciary Committee, the Justice Department, and the American Civil Liberties Union.http://en.wikipedia.org/wiki/Center_for_Media_and _Democracy
##### 307. Patrap
 Never, bring a hacksaw to a logging match.
Member Since: December 31, 1969 Posts: Comments:

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