# 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.)

r

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.”

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##### 1106. cyclonebuster
Member Since: January 2, 2006 Posts: 131 Comments: 20508
##### 1104. nymore
 Quoting 1102. Xulonn:"A study from Fairleigh Dickinson University is making news today after one of its findings seemingly indicated that Fox News has the least-informed national audience, while NPR has the best-informed.""The study even determined that many people who watch no news at all are more informed than those who watch Fox News, and, of course, people who watch the Daily Show are more informed than both of the above." While I agree Fox news is garbage. I also think the news is spun on every network. All are trash.I did find it funny though that your post says a study is making news today. This study is almost 2 years old. Time to update the post and make it correct or was it your intention all along to purposefully deceive.
##### 1103. cyclonebuster
 Quoting 1102. Xulonn:"A study from Fairleigh Dickinson University is making news today after one of its findings seemingly indicated that Fox News has the least-informed national audience, while NPR has the best-informed.""The study even determined that many people who watch no news at all are more informed than those who watch Fox News, and, of course, people who watch the Daily Show are more informed than both of the above." I think they are a bit Higher than that pic....
Member Since: January 2, 2006 Posts: 131 Comments: 20508
##### 1102. Xulonn
 Quoting a hard-core AGW/CC denialist:Fox is a hell of a lot more legitiment than NBC!!!!!"A study from Fairleigh Dickinson University is making news today after one of its findings seemingly indicated that Fox News has the least-informed national audience, while NPR has the best-informed.""The study even determined that many people who watch no news at all are more informed than those who watch Fox News, and, of course, people who watch the Daily Show are more informed than both of the above."
Member Since: June 11, 2012 Posts: 0 Comments: 1635
##### 1101. Xulonn
 Quoting 1061. TropicalAnalystwx13:Hey guys,I'm in the process of writing for junior research paper on global warming. One of my main topics is debunking those who actively deny the existence of climate change.Does anybody have any good links to explore that I can talk about in my paper? Thanks in advance!Here's a link to a good website on the subject:GristEdited to go direct to the source - the other site's links were bad.
Member Since: June 11, 2012 Posts: 0 Comments: 1635
##### 1100. JohnLonergan
 Quoting 1097. schwankmoe:i would go so far as to say that FOX is the most 'legitiment' network out there. what, it's a perfectly cromulent word. I would say that it's the only 'legitiment' network out there.
Member Since: June 27, 2012 Posts: 0 Comments: 4048
##### 1099. Birthmark
 Quoting 1097. schwankmoe:i would go so far as to say that FOX is the most 'legitiment' network out there. what, it's a perfectly cromulent word.Just reading your post embiggened my understanding.
Member Since: October 30, 2005 Posts: 7 Comments: 5469
##### 1098. JohnLonergan
 Quoting 1096. Birthmark:Ah, but you're not *sure*. See how that works? lol But I can express my uncertainty as , Judith just doesn't know.
Member Since: June 27, 2012 Posts: 0 Comments: 4048
##### 1097. schwankmoe
 Quoting 1071. Neapolitan:I believe this comment speaks for itself, so nothing more need be added...i would go so far as to say that FOX is the most 'legitiment' network out there. what, it's a perfectly cromulent word.
##### 1096. Birthmark
 Quoting 1095. JohnLonergan:I think the "uncertainty monster" has take over her brain.Ah, but you're not *sure*. See how that works? lol
Member Since: October 30, 2005 Posts: 7 Comments: 5469
##### 1095. JohnLonergan
 Quoting 1092. Birthmark:This seems to be Curry's understanding of climate science generally in the last few years. She's gone from making the occasional useful observation to hand-waving puzzlement.I think the "uncertainty monster" has take over her brain.
Member Since: June 27, 2012 Posts: 0 Comments: 4048
##### 1093. Birthmark
 Quoting 1091. JohnLonergan:A little afternoon snarkBut it's outstandingly good snark! :)
Member Since: October 30, 2005 Posts: 7 Comments: 5469
##### 1092. Birthmark
 Quoting 1089. JohnLonergan:Curry’s contribution can be summed up asThe reasoning behind the Miller et al. conclusions is rather complex, with a number of assumptions, I’m not sure what to make of their arguments...This seems to be Curry's understanding of climate science generally in the last few years. She's gone from making the occasional useful observation to hand-waving puzzlement.
Member Since: October 30, 2005 Posts: 7 Comments: 5469
##### 1091. JohnLonergan
Member Since: June 27, 2012 Posts: 0 Comments: 4048
##### 1090. Birthmark
Member Since: October 30, 2005 Posts: 7 Comments: 5469
##### 1089. JohnLonergan
Member Since: June 27, 2012 Posts: 0 Comments: 4048
##### 1088. RevElvis
 What is TPP & why should you care? (YES it does apply to Climate Change)DailyKos.comTruth-Out.org/BuzzFlash
##### 1087. ScottLincoln
 Quoting 1084. georgevandenberghe:Please note.That hiss is natural.Tire pressure has always gone in cycles.It was flatter several times before a long time ago.Tires run better flat.If I stop and deal with it the economic damage from my being latewill be extreme.My tire pressure has been low before. That was before the pile-up involving the nail-carrying 18-wheeler. So how can you prove it wasn't due to a cold weather spell?
##### 1085. FLwolverine
 Quoting 1084. georgevandenberghe:Please note.That hiss is natural.Tire pressure has always gone in cycles.It was flatter several times before a long time ago.Tires run better flat.If I stop and deal with it the economic damage from my being latewill be extreme.Nicely done!
##### 1084. georgevandenberghe
 Quoting 1079. cyclonebuster:The sheeple at "Fox News" can't change a flat tire...Please note.That hiss is natural.Tire pressure has always gone in cycles.It was flatter several times before a long time ago.Tires run better flat.If I stop and deal with it the economic damage from my being latewill be extreme.
##### 1083. Patrap
 Quoting 1078. Birthmark:Maybe.Maybe not.I'm not sure it's all that important.Me neither, I jus though they needed a bone to chew on, since it is Tuesday.Law of accelerating returns is a good un
Member Since: July 3, 2005 Posts: 430 Comments: 131147
##### 1082. RevElvis
 Climate change pact signed by California, Oregon, Washington and British Columbia (Mercury News)From left, Mary Polak, environment minister of British Columbia, Oregon Gov. John Kitzhaber, Washington Gov. Jay Inslee and California Gov. Jerry Brown (Marcio Jose Sanchez / AP)
##### 1081. Neapolitan
Member Since: November 8, 2009 Posts: 4 Comments: 14141
##### 1080. barbamz
 Sierra Leone: Farmers in 'Life and Death' Battle With Climate Shifts - StudyBy Jake Lucas, 25 October 2013London — Changing weather patterns as a result of climate change are making life much harder for farmers in war-ravaged Sierra Leone, a country already battling with poverty, a recent study says.With 70 percent of people depending on farming for a living, erratic rainfall leading to decreasing yields is forcing many to find other ways of making money, sometimes creating additional problems, according to the study's authors."This is about life and death, so there is need for them to come up with something that will keep them going," study leader Kabba Santigie Bangura of the University of Sierra Leone's department of geography said at the Mary Kingsley Zochonis Lecture at King's College this week.Farmers in Sierra Leone rely on a traditional pattern of a six-month rainy season followed by a six-month dry season to know when to plant their crops.But 76 percent of the 250 farmers who participated in the study said those weather patterns are seriously changing. Bangura and his co-authors recount that farmers noticed that now "rainfall does not follow any regular pattern."Adding to the problem, Bangura said there is a lack of reliable meteorological information to help farmers track and plan for the changes. ...
##### 1079. cyclonebuster
 Quoting 1068. tramp96:Fox is a hell of a lot more legitiment than NBC!!!!!The sheeple at "Fox News" can't change a flat tire...
Member Since: January 2, 2006 Posts: 131 Comments: 20508
##### 1078. Birthmark
 Quoting 1076. Patrap:Was it the Climate Change induced Blocking High that sent Sandy into da Jersy Shore?Maybe.Maybe not.I'm not sure it's all that important.
Member Since: October 30, 2005 Posts: 7 Comments: 5469
##### 1077. Birthmark
 Quoting 1061. TropicalAnalystwx13:Hey guys,I'm in the process of writing for junior research paper on global warming. One of my main topics is debunking those who actively deny the existence of climate change.Does anybody have any good links to explore that I can talk about in my paper? Thanks in advance!I'll echo what others have said.Skeptical Science --always go to the papers cited in the articles.Real Climate --I've linked you to the "Start Here" page has a ton of excellent links. Again, always look at the linked papers.anti-AGW papers debunked which is nothing but links to papers (and occasionally blog posts which you can ignore if you like)Enjoy your project!
Member Since: October 30, 2005 Posts: 7 Comments: 5469
##### 1076. Patrap
 Was it the Climate Change induced Blocking High that sent Sandy into da Jersy Shore?
Member Since: July 3, 2005 Posts: 430 Comments: 131147
##### 1075. Birthmark
 Quoting 1070. Cochise111:Another warmist "study" on temperatures in Greenland and Baffin Island shown to be "cherry-picked" as well as bogus. The claim was that the area is warmer than it has been in the past 44,000 years. LinkWell, if that's the case, then the author is wasting time blogging about it. Time to publish or perish, as the saying goes.Either way, the take home from the abstract is this: "the Eastern Canadian Arctic to show that 5000 years of regional summertime cooling has been reversed." There is no other physical reason, aside from CO2, for such a reversal to occur. Whether it's the warmest it's been in 5000 or 44000 is really of little consequence.
Member Since: October 30, 2005 Posts: 7 Comments: 5469
##### 1074. cyclonebuster
 Quoting 1050. ScottLincoln:Hard to say or quantify, at least for me. Someone else might be better-suited for that question.If I had to take a guess, I would say that probably so, to some extent. The atmosphere we live in today is not the same as 30 years ago. The energy balance is not the same, and different parts of the world are gaining heat at different rates. It would be hard to imagine how this would not change regional interactions and/or known internal variability.The main point still remains, however, it's the change in greenhouse gas concentrations that is adding heat to the climate system. Internal variability cannot do that.Sounds like it is no different than compressing air.... The more air you compress the more heat you will create....
Member Since: January 2, 2006 Posts: 131 Comments: 20508
##### 1073. Patrap
 I like the Guitar.
Member Since: July 3, 2005 Posts: 430 Comments: 131147
##### 1072. Birthmark
 Quoting 1068. tramp96:Fox is a hell of a lot more legitiment than NBC!!!!!Maybe, but first I'll have to look up "legitiment."It should also be noted, 1)that NBC news routinely crushes Fox"News" in the ratings; 2)that I don't watch either of them.TV news is crap. It's only real use, imo, is for live events. Even then they seem compelled to have commentators babble either the obvious or stupidities throughout.
Member Since: October 30, 2005 Posts: 7 Comments: 5469
##### 1071. Neapolitan
 Quoting 1068. tramp96:Fox is a hell of a lot more legitiment than NBC!!!!!I believe this comment speaks for itself, so nothing more need be added...
Member Since: November 8, 2009 Posts: 4 Comments: 14141
##### 1069. FLwolverine
 Quoting 1061. TropicalAnalystwx13:Hey guys,I'm in the process of writing for junior research paper on global warming. One of my main topics is debunking those who actively deny the existence of climate change.Does anybody have any good links to explore that I can talk about in my paper? Thanks in advance!This might also be useful. Earth: the Operator's Manual Link. This links to a page with several short videos providing information for talking to "ostriches". Richard Alley narrated the ones that I've watched so far. It's another tool in preparing to rebut deniers, although you may want links to some of the underlying info.
##### 1067. Patrap
 On second thought....
Member Since: July 3, 2005 Posts: 430 Comments: 131147
##### 1066. georgevandenberghe
 Quoting 1049. indianrivguy:The problem on this blog is not the spam by the deniers.. it is the fact that you all insist on giving them value by responding. If everyone one of us minused and flagged the bullcrap, YOU could do what the blog owner refuses to do, clean this place up.. I think Dr. Rood is more concerned with how many posts he gets, rather than the quality and truthfulness of its content. So, really, quite complaining about the same crap, posted by the same people day after day.. it is YOUR fault it keeps appearing.I agree but would further add that as long as these deniers are out there I want to see what they are thinking, evaluate it and likely reject it post by post without comment. If they are blocked we will start living in our own sanitized world where we do not realize there are still a lot of misguided people out there.
##### 1065. ScottLincoln
 Quoting 1061. TropicalAnalystwx13:Hey guys,I'm in the process of writing for junior research paper on global warming. One of my main topics is debunking those who actively deny the existence of climate change.Does anybody have any good links to explore that I can talk about in my paper? Thanks in advance!I concur, Skeptical Science is one of the best repositories out there for climate science concepts. It typically does a good job of sourcing where the info comes from. I would suggest picking a few big claims, then talking about what scientists actually say about the topic. Many times there is a limited amount of truth to skeptic concerns, but there is a crucial piece missing, either important context, or newer research.Make sure to not cite skeptical science in your paper (unless doing so indirectly, such as by saying that it is a good site to use to debunk science myths) - cite the original journal articles themselves!
##### 1064. Neapolitan
 Quoting 1058. ScottLincoln:The math it does is super simple.1. We have several different datasets on a monthly timestep for many different forcings... solar, volcanic, anthropogenic, and enso.2. The user enters a lag (in months), a short-term effective efficacy (W/sq meter per unit change), and a short-term climate sensitivity (C/W/sq meter).3. A temperature influence for each dataset is calculated based upon the simple lag and multiplier as described in #2.4. Values are averaged over an entire calendar year.Cool. I'll email you in a bit; I have a couple of questions...
Member Since: November 8, 2009 Posts: 4 Comments: 14141
##### 1063. Neapolitan
 Quoting 1059. JohnLonergan:Mike Lockwood mikes it clear that Paul Hudson misrepresented what he said: There is an update at Stoat this morning with some more comment.I bring this up again because I believe that the utter dishonesty and mendacity of people like Hudson must be constantly pointed out.So as I said yesterday, Paul Hudson is a liar. But let me rephrase that: he's a damn liar with a clear lack of journalistic ethics. IOW, he's Fox material only; he should be kept far away from any news organization that wants to be considered legitimate...
Member Since: November 8, 2009 Posts: 4 Comments: 14141
##### 1062. JohnLonergan
 Quoting 1061. TropicalAnalystwx13:Hey guys,I'm in the process of writing for junior research paper on global warming. One of my main topics is debunking those who actively deny the existence of climate change.Does anybody have any good links to explore that I can talk about in my paper? Thanks in advance!I'd start with the Climate Change tab at the top of the page, the Feeling Skeptical button takes you directly to SkepticalScience where there are a lot of articals on different skeptical arquments.SkepticalScience gives links to the scientific literature in its discussion.RealClimate.org has good information here Anti-AGW papers debunked gives a list of specific skeptical papers and links to peer-reviewed rebuttals.
Member Since: June 27, 2012 Posts: 0 Comments: 4048
##### 1061. TropicalAnalystwx13
 Hey guys,I'm in the process of writing for junior research paper on global warming. One of my main topics is debunking those who actively deny the existence of climate change.Does anybody have any good links to explore that I can talk about in my paper? Thanks in advance!
##### 1060. Torito
 Testing for bots....Global warming is a hoax.Had to do it.^
##### 1059. JohnLonergan
 Mike Lockwood mikes it clear that Paul Hudson misrepresented what he said: There is an update at Stoat this morning with some more comment.I bring this up again because I believe that the utter dishonesty and mendacity of people like Hudson must be constantly pointed out.
Member Since: June 27, 2012 Posts: 0 Comments: 4048
##### 1058. ScottLincoln
 Quoting 1053. Neapolitan:Well, I develop sophisticated web apps for a living; let me have a look...The math it does is super simple.1. We have several different datasets on a monthly timestep for many different forcings... solar, volcanic, anthropogenic, and enso.2. The user enters a lag (in months), a short-term effective efficacy (W/sq meter per unit change), and a short-term climate sensitivity (C/W/sq meter).3. A temperature influence for each dataset is calculated based upon the simple lag and multiplier as described in #2.4. Values are averaged over an entire calendar year.
##### 1057. FLwolverine
 Quoting 1054. ScottLincoln:Jim, I thought one of the mods mentioned on Dr. Masters' blog thread recently that 10 is the magic number. If a post is flagged by 10 different people, it is automatically hidden or removed (can't remember which) without moderator interaction.I thnk there is still some moderator discretion (something was said about not letting a group of people gang up on one commenter), but I agree that the - and ! Buttons are worth a try. Everyone needs to participate.

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