# 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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##### 1207. Patrap
 Thanx for your knowledgeable input.Now you can go back to playing met in Jeff's entry.
Member Since: July 3, 2005 Posts: 439 Comments: 137185
##### 1206. Torito
 Bot check.GLOBAL WARMING IS A HOAX.
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##### 1205. Patrap
 Science has no time for emotions, as the Science on AGW is as strong as one will find in any field.The time to discuss "is it real", was past a decade ago.NOAA has all the relevant info as to causation and feedbacks occurring.This is not FB, nor a Main blog board. We deal with the science of AGW here, not whether or not it exist.And to run to Masters entry whining like a child is bad form....as your post was "all" inclusive as to posters here I gather. You will find the dissenters on your side "there", as they clutch to any Hope of AGW being er, a Hoax.Good luck with that group.
Member Since: July 3, 2005 Posts: 439 Comments: 137185
##### 1204. GTstormChaserCaleb
 Quoting 1200. Daisyworld:I'm not entirely convinced that you took that class, otherwise you should be able to answer that question. The recent precipitous rise of CO2 in the Earth's atmosphere is due to the burning of fossil fuels, far eclipsing any other CO2 emitted from the natural carbon cycle. There are no other "non-renewable energy resources" contributing to the rise in CO2 as the burning of fossil fuels do. If you took PHYS 142, you would already know this.That's your business whether you believe I took the class or not as I know what I took, so don't tell me I didn't take this class. Besides like I said I took the class 5 years ago. Next thing you know you're probably going to call me a liar. And you repeated what I said in comment post 1199 about the burning of fossil fuels being the main contributor to CO2, so if you're done being rude, we can continue on with this conversation. Thanks and have a nice day.
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##### 1203. JohnLonergan
 SALON interview with Yale economist William Nordhaus:William Nordhaus: Smoking can teach us about climate changeA Yale economist explains why we need to put a price on carbonWe’re uncertain about the effects of climate change the way we’re uncertain that smoking causes cancer, says economist William Nordhaus. “Uncertainty,” in other words, really isn’t a good reason for us not to do everything possible to stem carbon emissions.In the latest of his series of books on climate change, “The Climate Casino: Risk, Uncertainty and Economics for a Warming World,” Nordhaus, the Sterling Professor of Economics at Yale University, delivers a primer of sorts on the social, political and economic factors at play in the climate debate. It’s not whether climate change is happening, he suggests, but what we can and should do about it, that’s the true question for our time.Nordhaus spoke with Salon about his case for a putting a price on carbon, and what we’d have to do to afford and embrace what he says is the only way we have to slow global warming. This interview has been lightly edited for length and clarity.Read more >>
Member Since: June 27, 2012 Posts: 0 Comments: 4517
##### 1200. Daisyworld
 Quoting 1199. GTstormChaserCaleb:I've taken that class already, but it was 5 years ago. Here is my thing I want to ask you. It's the human causes of GW. Is it every country in the world contributing to GW in some way or is it just the countries that have the resources to contribute to GW. Reason I ask this is because we seem to equip the rising levels of CO2 and other greenhouse gases to GW which are produced from burning of fossil fuels and other non-renewable energy resources. So I'm thinking countries that aren't that technologically advanced or still relying on donkey carts and wagons as a form of transportation do they play a part in this as well and it what ways?I'm not entirely convinced that you took that class, otherwise you should be able to answer that question. The recent precipitous rise of CO2 in the Earth's atmosphere is due to the burning of fossil fuels, far eclipsing any other CO2 emitted from the natural carbon cycle. There are no other "non-renewable energy resources" contributing to the rise in CO2 as the burning of fossil fuels do. If you took PHYS 142, you would already know this.
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##### 1199. GTstormChaserCaleb
 Quoting 1198. Daisyworld:Caleb, I highly suggest you take PHYS 142 (Introduction to Environmental Science) at ERAU when you get the chance. It will help you establish a baseline knowledge needed to understand both climate change and the scientific process.I've taken that class already, but it was 5 years ago. Here is my thing I want to ask you. It's the human causes of GW. Is it every country in the world contributing to GW in some way or is it just the countries that have the resources to contribute to GW. Reason I ask this is because we seem to equip the rising levels of CO2 and other greenhouse gases to GW which are produced from burning of fossil fuels and other non-renewable energy resources. So I'm thinking countries that aren't that technologically advanced or still relying on donkey carts and wagons as a form of transportation do they play a part in this as well and it what ways?
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##### 1198. Daisyworld
 Quoting 1197. GTstormChaserCaleb:What!?!? so that video I posted isn't scientific? Ruth Curry's graphics and charts must be flawed then. All those collected sediment core samples stored in the Woods hole Oceanographic Institution is not scientific? C'mon that's not fair.Caleb, I highly suggest you take PHYS 142 (Introduction to Environmental Science) at ERAU when you get the chance. It will help you establish a baseline knowledge needed to understand both climate change and the scientific process.
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##### 1197. GTstormChaserCaleb
 Quoting 1195. Birthmark:Scientifically, there aren't two sides. That fact is visible from the scientific literature.It goes into the recycle bin because the points that were made are invalid scientifically. (See: Posts 1189 and 1191 above.) Science always trumps rhetoric in the real world.What!?!? so that video I posted isn't scientific? Ruth Curry's graphics and charts must be flawed then. All those collected sediment core samples stored in the Woods hole Oceanographic Institution is not scientific? C'mon that's not fair.
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##### 1196. Daisyworld
 Quoting 1194. GTstormChaserCaleb:Didn't know I was turning in an analytical report? I would reference the page, but I forgot my log in. So here is a a href="Link" target="_blank">Link, I guess if it doesn't support your cause it automatically goes into the recycle bin. That's ok because I will continue to show both sides of the argument on here. And science as that video I posted in 1176 shows that the Arctic Ice Melt may alter the thermohaline conveyor belt replacing more fresh water over top of ocean water stopping the water pump known as the Gulf Stream from bring warmer waters to places like the UK and the Northeast US thus causing colder winters like we saw back in the 80s.Okay, thanks for the link. Unfortunately, only those who can log into ERNIE will be able to access it. For the record, the reference is:Sorokhtin, Oleg G., George V. Chilingar, Leonid F. Khilyuk, "Global Warming and Global Cooling — Evolution of Climate on Earth", Developments in Earth and Environmental Sciences, Volume 5, 2007, Pages xi–xvi, 1–313.However, it doesn't look like the full paper is available at the Hunt Library in ERNIE (the school is not subscribed to the journal). So, did you actually read the paper? Or did you just glean the information you wanted from the Foreword?Even still, the foreword discusses that the "debate" is occurring in public policy and the media. This is disturbing because in science, there is no debate, yet many believe there is. I vehemently oppose the perpetuation of the myth that there are two sides to the subject of human-induced climate change. I suggest you focus your efforts on either understanding the science (which is quite clear that humans are the primary cause of the current global warming trend), or learning to separate the facts from the lies in this so-called "debate" in the public and media.
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##### 1194. GTstormChaserCaleb
 Quoting 1193. Daisyworld:Agreed. In addition, the reference associated with the quote wasn't a complete one. They use APA6 at ERAU, so I'm surprised our esteemed alumni commenter did not include a reference for their researched quote.Didn't know I was turning in an analytical report? I would reference the page, but I forgot my log in. So here is a a href="Link" target="_blank">Link, I guess if it doesn't support your cause it automatically goes into the recycle bin. That's ok because I will continue to show both sides of the argument on here. And science as that video I posted in 1176 shows that the Arctic Ice Melt may alter the thermohaline conveyor belt replacing more fresh water over top of ocean water stopping the water pump known as the Gulf Stream from bring warmer waters to places like the UK and the Northeast US thus causing colder winters like we saw back in the 80s.
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##### 1193. Daisyworld
 Quoting 1192. Neapolitan:Your analysis is wrong...but it's no more wrong than the nonsense paper to which you linked. Here's a hint: when a purported scientific paper uses phrases such as "...they reflect the overwhelming 'humanocentric' bias of an environmentally zealous social community", you can pretty well guess it's coming from the wrong place.Agreed. In addition, the reference associated with the quote wasn't a complete one. They use APA6 at ERAU, so I'm surprised our esteemed alumni commenter did not include a reference for their researched quote.
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##### 1192. Neapolitan
 Quoting 1185. GTstormChaserCaleb:So what I take from this and this is just my analysis. Is that there is still studies that need to be done and the common people need to be more educated on the subject of climate change, so that they aren't taking what the media tells them as gospel. Also that we need to distinguish between natural changes in the climate and man-made changes to the climate. Also that it is more important to focus on scientific observations rather than theoretical computer models. It is just that computer models are giving predictions into the future and in terms of climate that could be a long ways into the future whereas scientific observations are in the present. I will say we are in a Global Warming trend when you look at temperatures Globally warming since the Industrial Revolution, but the question is how much further will the Earth continue to warm and for how long more?Your analysis is wrong...but it's no more wrong than the nonsense paper to which you linked. Here's a hint: when a purported scientific paper uses phrases such as "...they reflect the overwhelming 'humanocentric' bias of an environmentally zealous social community", you can pretty well guess it's coming from the wrong place.
Member Since: November 8, 2009 Posts: 4 Comments: 14845
##### 1191. Daisyworld
 Quoting 1186. yoboi:The Mauna Loa Observatory is part of the National Oceanic and Atmospheric Administration (NOAA), Earth System Research Laboratory (ESRL), Global Monitoring Division (GMD) in the USA. The continuous, high-precision measurement of changes in atmospheric CO2 concentrations was started in March 1958 at the Mauna Loa Observatory by Charles David Keeling.Yes, yes. Good data. But like most who deny that human-induced climate change exists (let alone the fact that humans are the dominant factor behind the current warming) you focus on only a tiny fraction of the information needed to base a sound conclusion:
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##### 1185. GTstormChaserCaleb
 Quoting 1183. GTstormChaserCaleb:Global Warming and Global Cooling: Evolution of Climate on EarthOleg G. Sorokhtin, George V. Chilingar, Leonid F. KhilyukSo what I take from this and this is just my analysis. Is that there is still studies that need to be done and the common people need to be more educated on the subject of climate change, so that they aren't taking what the media tells them as gospel. Also that we need to distinguish between natural changes in the climate and man-made changes to the climate. Also that it is more important to focus on scientific observations rather than theoretical computer models. It is just that computer models are giving predictions into the future and in terms of climate that could be a long ways into the future whereas scientific observations are in the present. I will say we are in a Global Warming trend when you look at temperatures Globally warming since the Industrial Revolution, but the question is how much further will the Earth continue to warm and for how long more?
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##### 1183. GTstormChaserCaleb
 Global Warming and Global Cooling: Evolution of Climate on EarthOleg G. Sorokhtin, George V. Chilingar, Leonid F. Khilyuk
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##### 1182. Daisyworld
 Quoting 1181. overwash12: Hey Now! I don't spread that kinda stuff. I calls it how I sees it!And what you are choosing to see and focus on are lies and propaganda. Please read Dr. Master's entire blog entry on The Manufactured Doubt Industry so you know how you are contributing to the spread of lies and propaganda about human-induced climate change
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##### 1181. overwash12
 Quoting 1173. Daisyworld:Then you must be reading your past comments. Hey Now! I don't spread that kinda stuff. I calls it how I sees it!
Member Since: June 24, 2007 Posts: 0 Comments: 1498
##### 1180. Patrap
 When you add all this C02 en masse to the closed Earth System, what did they think was going to happen?Now that were at 400ppm and rising, the feedbacks are starting to accelerate.Toss in a massive Methane release and bada boom' The Climate Change Pandora's Box is creaking open, and lil wiggly things will continue to fly out.Buckle up,...
Member Since: July 3, 2005 Posts: 439 Comments: 137185
##### 1179. Daisyworld
 Quoting 1177. yoboi:I agree with you....the best movie too watch is a movie that is not edited with failed computer models....That's another lie, yoboi. Just as Weather Underground's climate change section explains to everyone.Why do you continue to post lies when you know they're not true?
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##### 1176. GTstormChaserCaleb
 Never thought I would see Dr. Roods blog get more attention than Dr. Masters. I guess hurricane season is dead and AGW is alive and well. Have you guys watched this yet?
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##### 1173. Daisyworld
 Quoting 1170. overwash12: ... I get confused from reading all the propaganda these days!Then you must be reading your past comments.
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##### 1171. Daisyworld
 Quoting 1166. yoboi:We are gaining ice at both poles....Still trying to understand how warming causes more ice.....*sigh*That's a lie, and you know it.
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##### 1170. overwash12
 Quoting 1166. yoboi:We are gaining ice at both poles....Still trying to understand how warming causes more ice..... More moisture in the air with a warming Earth,or was it more droughts. I get confused from reading all the propaganda these days!
Member Since: June 24, 2007 Posts: 0 Comments: 1498
##### 1168. Astrometeor
 Quoting 1166. yoboi:We are gaining ice at both poles....Still trying to understand how warming causes more ice.....I thought you were going to make a new handle?
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##### 1167. overwash12
 Quoting 1165. Birthmark:Yeah, ain't that something? Imagine! The Arctic gets cold in winter? And look! Just one more standard deviation and the ice will have "recovered" to the disastrous long-term trend! Some of you folks... LOL A few colder than average winters will put it right back!
Member Since: June 24, 2007 Posts: 0 Comments: 1498
##### 1163. Daisyworld
 Quoting 1162. overwash12:Guess what is taking place right now? Arctic ice is expanding in volume! Winter is around the corner.And your subjective declaration is related to climate change... because...?
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##### 1162. overwash12
 Guess what is taking place right now? Arctic ice is expanding in volume! Winter is around the corner.
Member Since: June 24, 2007 Posts: 0 Comments: 1498
##### 1161. Xandra
 From Arctic News Blog:Greenland Sea hit by M5.3 EarthquakeAn earthquake with a magnitude of 5.3 on the Richter scale hit the Greenland Sea near Svalbard on October 28, 2013.For a long time, huge sea surface temperature anomalies have shown up in the area where the earthquake hit. The image below compares the situation before and after the earthquake hit.These huge sea surface temperature anomalies were discussed before, in the September 19, 2013, post Is the North Pole now ice-free?This post mentions that sea surface temperatures in some spots close to Svalbard are far higher than even in the waters closer to the Atlantic Ocean. In some of these spots, sea surface temperatures are well over 10°C (50°F).The post continues: Where does this heat come from? These hot spots could be caused by undersea volcanic activity; this is the more dangerous as this area has seen methane bubbling up from destabilized hydrates before; the dangers of this situation have been discussed repeatedly, e.g. in the April 2011 post Runaway Global Warming.Indeed, the big danger is large abrupt release of methane from destabilized hydrates. At the moment, the amount of methane entering the atmosphere over the Arctic Ocean is already huge, as illustrated by the image below that shows high methane readings over the past few days.We'll keep monitoring the situation.
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##### 1160. JohnLonergan
 Influence of Arctic sea ice on European summer precipitationAbstractThe six summers from 2007 to 2012 were all wetter than average over northern Europe. Although none of these individual events are unprecedented in historical records, the sequence of six consecutive wet summers is extraordinary. Composite analysis reveals that observed wet summer months in northern Europe tend to occur when the jet stream is displaced to the south of its climatological position, whereas dry summer months tend to occur when the jet stream is located further north. Highly similar mechanisms are shown to drive simulated precipitation anomalies in an atmospheric model. The model is used to explore the influence of Arctic sea ice on European summer climate, by prescribing different sea ice conditions, but holding other forcings constant. In the simulations, Arctic sea ice loss induces a southward shift of the summer jet stream over Europe and increased northern European precipitation. The simulated precipitation response is relatively small compared to year-to-year variability, but is statistically significant and closely resembles the spatial pattern of precipitation anomalies in recent summers. The results suggest a causal link between observed sea ice anomalies, large-scale atmospheric circulation and increased summer rainfall over northern Europe. Thus, diminished Arctic sea ice may have been a contributing driver of recent wet summers.Link to complete paper and video presentation
Member Since: June 27, 2012 Posts: 0 Comments: 4517
##### 1158. bappit
 The denialist strategizers that Naomi Oreskes writes about, such as the types at Heartland Institute, do an interesting thing. They say we must deny science in order to prevent new governmental regulations. Since they are ideologs who believe that governmental regulation is worse than any problem it might solve, they think they are "doing the right thing." The kicker is that by going to the extreme of denying the science, they implicitly assume that government regulation is the way to solve the problem of AGW. (Why else tie their main goal to denying the validity of the science?) So their extreme strategy of combating government regulation paints them into a corner. If they ever admit to the validity of the science, by their own assumptions they automatically admit that we need government regulations.So they will never encourage people to listen to reason about the science because that would immediately defeat their main agenda.
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##### 1157. FLwolverine
 Quoting 1153. cyclonebuster:She doesn't want solutions so she banned me..May I copy the info over there?
Member Since: January 6, 2013 Posts: 3 Comments: 2714

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