# 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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##### 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: 2689
##### 1156. FLwolverine
 Quoting 1149. Cochise111:Totally cherry picked and out of context. The program - with three scientists and a coastal management guy from Florida - is actually pretty good, and it's clear from Dr Long's statement that she means the IPCC is underestimating the effects of climate change - that no one can predict any longer whether we can actually keep temperature increases under 2% by cutting emissions.Here is the link to the whole program: LinkI think the Florida guy is just blowing smoke when he says Miami won't have to be abandoned.Added: here's the link to the New York Times sea level site shown in the video - Link
Member Since: January 6, 2013 Posts: 3 Comments: 2689
##### 1153. cyclonebuster
 Quoting 1148. FLwolverine:#1146 - CB - your post would be very appropriate over on Angela Fritz's blog too.Good article; terrible news.She doesn't want solutions so she banned me..
Member Since: January 2, 2006 Posts: 136 Comments: 20883
##### 1148. FLwolverine
 #1146 - CB - your post would be very appropriate over on Angela Fritz's blog too.Good article; terrible news.
Member Since: January 6, 2013 Posts: 3 Comments: 2689
##### 1146. cyclonebuster
 Thawing Permafrost: The Speed of Coastal Erosion in Eastern Siberia Has Nearly DoubledOct. 29, 2013 The high cliffs of Eastern Siberia -- which mainly consist of permafrost -- continue to erode at an ever quickening pace. This is the conclusion which scientists of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research have reached after their evaluation of data and aerial photographs of the coastal regions for the last 40 years. According to the researchers, the reasons for this increasing erosion are rising summer temperatures in the Russian permafrost regions as well the retreat of the Arctic sea ice. This coastal protection recedes more and more on an annual basis. As a result, waves undermine the shores. At the same time, the land surface begins to sink. The small island of Muostakh east of the Lena Delta is especially affected by these changes. Experts fear that it might even disappear altogether should the loss of land continue.The interconnectedness is clear and unambiguous: The warmer the east Siberian permafrost regions become, the quicker the coast erodes. "If the average temperature rises by 1 degree Celsius in the summer, erosion accelerates by 1.2 metres annually," says AWI geographer Frank G%uFFFDnther, who investigates the causes of the coastal breakdown in Eastern Siberia together with German and Russian colleagues, and who has published his findings in two scientific articles.In these studies, he and his team evaluated high resolution air and satellite photos from 1951 to 2012 as well as measurements of the past four years. In addition, the researchers surveyed four coastal sections along the Laptev Sea (see map) and on the island of Muostakh.One example of the changes documented in their research are the warming summers. While the temperatures during the period of investigation exceeded zero degrees Celsius on an average of 110 days per year, the scientists counted a total of 127 days in the years 2010 and 2011. The following year, 2012, the number of days with temperatures above freezing increased to 134.This increase in temperature is not without consequences. Whereas a thick layer of sea ice used to protect the frozen soil almost all year round, it now recedes in this part of the Arctic for increasing periods of time during the summer months. The number of summer days on which the sea ice in the southern Laptew Sea vanishes completely grows steadily. "During the past two decades, there were, on average, fewer than 80 ice-free days in this region per year. During the past three years, however, we counted 96 ice-free days on average. Thus, the waves can nibble at the permafrost coasts for approximately two more weeks each year," explains AWI permafrost researcher Paul Overduin.The waves dig deep recesses into the base of the high coasts. The result: The undermined slopes break off bit by bit. During the past 40 years, the coastal areas surveyed retreated on average 2.2 meters per year. "During the past four years, this value has increased at least 1.6 times, in certain instances up to 2.4 times to reach 5.3 meters per year," says Paul Overduin.For the little island of Muostakh east of the harbour town of Tiksi, this may well mean extinction. "In fewer than one hundred years, the island will break up into several sections, and then it will disappear quickly," predicts Frank G%uFFFDnther. On its northern tip, the island shows fluctuating annual erosion rates between 10 and 20 meters per year, and it has already lost 24 per cent of its area in the past 60 years. Because the subsurface here consists of more than 80 per cent of ice that has formed within the soil, and since the ice is gradually melting, the island's surface collapses as well. The scientists speak of a 34 per cent loss in volume. "If one bears in mind that it took tens of thousands of years for the island to form through sedimentary deposition, then its disintegration is proceeding at a very rapid pace," says Paul Overduin.In addition, long-term studies conducted by AWI scientists show the impact of coastal erosion for the sea as well. Depending on the kind of erosion and the particular structure of the coast, between 88 and 800 tons of plant-, animal, and microorganism-based carbon are currently washed into the sea per year and kilometer of coastline -- these are materials that had been sealed in the permafrost thus far. With regard to the Laptev Sea, this translates into approximately one eighth of the organic carbon that is transported by the Lena River annually -- and the Lena is a river that encompasses a drainage basin the size of the Mediterranean. "We can, however, assume larger quantities if this accelerating coastal erosion we currently observe continues," the scientists write in their subject-specific paper for the Biogeosciences special volume: "Interactions between the land and sea in the Lena Delta Region." Once in the water, carbon may turn into carbon dioxide and, as a result, contribute to the acidification of the oceans: the composition of our oceans becomes less alkaline.Link
Member Since: January 2, 2006 Posts: 136 Comments: 20883
##### 1145. barbamz
 Climate migration 'a complex problem'Deutsche Welle English, October 29, 2013Climate change is forcing people to flee their homes. But when does someone become a climate migrant, and what does the status mean? Dina Ionesco from the International Organization for Migration, explains.
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##### 1144. FLwolverine
 Thanks, Pat.To the lurking Grothar, if one there be - many good wishes to you.
Member Since: January 6, 2013 Posts: 3 Comments: 2689
##### 1143. georgevandenberghe
 Quoting 1110. overwash12:That nail was put in the coffin for me this summer when the heat just wasn't there!DC summer was overall warmer than normal but much cooler than thelast three. August was cooler than the long term mean but notextreme. First year in several (I don't closely track) that July 25 planted sweetcorn did not quite mature but it's been a real long time (2006) since we had a cooler than normal August.
Member Since: February 1, 2012 Posts: 19 Comments: 3563
##### 1142. Patrap
 I'm sure he is a lurking from time to time.
Member Since: July 3, 2005 Posts: 438 Comments: 136318
##### 1141. FLwolverine
 Hi, Pat. Do you have any news of Grothar that you can share with us?
Member Since: January 6, 2013 Posts: 3 Comments: 2689
##### 1140. Patrap
Member Since: July 3, 2005 Posts: 438 Comments: 136318
##### 1139. georgevandenberghe
 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 remember the quote from the 1960s Rowan and Martin's Laugh InTV show."You think we're stupid. You're watching"OOPS.. Modification. I lost the Fox sign. I meant to take a deserved poke at Fox. By the way in the wild, foxes are rabies carriers.. they tolerate it longer than many species and can function for a while while spreading it. Parallels intended! GWV
Member Since: February 1, 2012 Posts: 19 Comments: 3563
##### 1138. cyclonebuster
 Quoting 1137. schwankmoe:nea's also a member of the illuminati, so he has plenty of help too.Spoken like a true Nephilim....
Member Since: January 2, 2006 Posts: 136 Comments: 20883
##### 1137. schwankmoe
 Quoting 1128. PensacolaDoug:So SP's would be a breeze.nea's also a member of the illuminati, so he has plenty of help too.
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##### 1136. ScottLincoln
 Quoting 1129. JohnLonergan:GISS September anomaly data is out, record equaling .74 http://data.giss.nasa.gov/gistemp/tabledata_v3/GL B.Ts dSST.txtBut wasn%u2019t the arctic the coldest in a century?Looks like 0.74C ties the previous record from 2005.Using my crude attempt to approximate temperature contributions from various natural factors and the background anthropogenic warming rate, I forecasted 0.66C anomaly, assuming neutral ENSO. The 95% uncertainty bars on that forecast would probably be approximately 0.1C either way. To be within the range, we would need roughly 0.5C average for the rest of the year. To be spot on, we'd need roughly 0.87C average for the rest of the year (seems unlikely). Once the year is done and more data comes in for each of the natural factors (ENSO/Volcanic aerosols/Solar), I should be able to do a "corrected hindcast," which will basically say what the forecast should have been, if we had a perfect forecast for the natural forcings.
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##### 1135. ScottLincoln
 Quoting 1125. Birthmark:Yeah, you probably want to think a bit about what you read, if you read.(If you look at and think about the numbers involved...well, it doesn't really say anything that you'd like. lol)If you look at the numbers involved and how they calculated them, you can see how bad the critiquers are at arithmetic. It was a very bad attempt to critique a paper done by people far more experienced in that field, and it shows.
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##### 1134. Patrap
 Come on in, its Hump Day.The warming continue's, unabated
Member Since: July 3, 2005 Posts: 438 Comments: 136318
##### 1133. Patrap
 No, your link says it all, as the wu prompt tells us its not worthy.Anything else?
Member Since: July 3, 2005 Posts: 438 Comments: 136318
##### 1131. barbamz
 The Guardian is focussing on the strange political situation in Australia with its new government concerning CC:Climate change chairman attacks policy 'flip-flopping' and lack of consensusKatharine Murphy deputy political editortheguardian.com, Wednesday 30 October 2013 05.19 GMT Bernie Fraser criticises Abbott's 'extreme' position and says policy reversals create uncertainty for investorsMissing logic of Australian prime minister's denial of climate change link to bushfiresPosted by Graham Readfearn, Tuesday 29 October 2013 02.32 GMT theguardian.com The popular climate sceptic debating trick used by Tony Abbott fails the logic test
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##### 1130. JohnLonergan
 Guess what?Climate change is happening, it has always happened, and it is happening faster then it should because of we humans, and our burning fossil fuels. ......Please enjoy this video from Hank as he dismisses 10 common climate denier memes.
Member Since: June 27, 2012 Posts: 0 Comments: 4411
##### 1129. JohnLonergan
 GISS September anomaly data is out, record equaling .74 http://data.giss.nasa.gov/gistemp/tabledata_v3/GL B.Ts dSST.txtBut wasn%u2019t the arctic the coldest in a century?
Member Since: June 27, 2012 Posts: 0 Comments: 4411
##### 1128. PensacolaDoug
 Quoting 1053. Neapolitan:Well, I develop sophisticated web apps for a living; let me have a look...So SP's would be a breeze.
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##### 1127. cyclonebuster
 Typical ignorants at Fox News....Link....
Member Since: January 2, 2006 Posts: 136 Comments: 20883
##### 1126. RevElvis
 Hurricane Sandy's Path Could Become More Frequent For Other StormsHuffingtonPost.com (Video Interview / Columbia Earth Institute)
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##### 1124. cyclonebuster
 Quoting 1123. Astrometeor:That would work, but California is so heavily developed where Google is located, it would be mightily hard for them to build a piping infrastructure there. A barge isn't hard to make, plus it's capable of being moved if one needs it to be.To hard to get permits....
Member Since: January 2, 2006 Posts: 136 Comments: 20883
##### 1123. Astrometeor
 Quoting 1122. cyclonebuster:Doesn't seem to accessible when you you have to use a barge to get to the water when all you have to do is insulate it and pipe it onshore...That would work, but California is so heavily developed where Google is located, it would be mightily hard for them to build a piping infrastructure there. A barge isn't hard to make, plus it's capable of being moved if one needs it to be.
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##### 1122. cyclonebuster
 Quoting 1119. Astrometeor:Well, yes, but for a large-scale system like a data center you would want a good, easily accessible amount of water on-hand.Doesn't seem to accessible when all you have to do is use a barge to get to the water when all you have to do is insulate it and pipe it onshore...
Member Since: January 2, 2006 Posts: 136 Comments: 20883
##### 1121. Astrometeor
 Quoting 1116. StallworthSwing:Haha. Very funny. A boatload of Nea's sockpuppets just got banned within the last two days. What does that tell you?I was hoping you would say drawer full of sockpuppets...
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##### 1120. FLwolverine
 Quoting 1116. StallworthSwing:Haha. Very funny. A boatload of Nea's sockpuppets just got banned within the last two days. What does that tell you?That you like to spout nonsense?
Member Since: January 6, 2013 Posts: 3 Comments: 2689
##### 1119. Astrometeor
 Quoting 1117. cyclonebuster:Nah you can do that with well water...Well, yes, but for a large-scale system like a data center you would want a good, easily accessible amount of water on-hand.
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##### 1118. overwash12
 Quoting 1114. FLwolverine:Neither you nor anyone else has proven it isn't bad. Would it be more truthful for you to say: "AGW isn't the same because I believe the science that says smoking is harmful but I refuse to read the science that says AGW s harmful." I'll smoke a cig and cut firewood for the upcoming winter!We still have that choice!
Member Since: June 24, 2007 Posts: 0 Comments: 1498
##### 1117. cyclonebuster
 Quoting 1108. Astrometeor:I heard one rumor that it could be a data center. Lots of computers put together in one spot need a way to cool off, and apparently one of the best ways is to use water, a barge, and some piping and do a transfer of heat similar to what nuke plants do.Nah you can do that with well water...
Member Since: January 2, 2006 Posts: 136 Comments: 20883
##### 1115. FLwolverine
 Hey, I just responded to Overwash who was conversing with Nea! Does that mean I'm a sock puppet?
Member Since: January 6, 2013 Posts: 3 Comments: 2689
##### 1114. FLwolverine
 Quoting 1112. overwash12: No,I say it's not the same. Bad analogy. Smoking has been proven to be bad. AGW is not the same.Neither you nor anyone else has proven it isn't bad. Would it be more truthful for you to say: "AGW isn't the same because I believe the science that says smoking is harmful but I refuse to read the science that says AGW s harmful."
Member Since: January 6, 2013 Posts: 3 Comments: 2689
##### 1113. overwash12
 Is Dr. Rood having difficulties posting a new entry? I keep clicking on New Entry when it pops up and it takes me back to this one.
Member Since: June 24, 2007 Posts: 0 Comments: 1498
##### 1112. overwash12
 Quoting 1111. Neapolitan:That makes sense. It's like a heavy smoker claiming that because he hasn't yet contracted cancer, cigarettes are perfectly good for you... No,I say it's not the same. Bad analogy. Smoking has been proven to be bad. AGW is not the same.
Member Since: June 24, 2007 Posts: 0 Comments: 1498
##### 1111. Neapolitan
 Quoting 1110. overwash12:That nail was put in the coffin for me this summer when the heat just wasn't there!That makes sense. It's like a heavy smoker claiming that because he hasn't yet contracted cancer, cigarettes are perfectly good for you...
Member Since: November 8, 2009 Posts: 4 Comments: 14688
##### 1110. overwash12
 That nail was put in the coffin for me this summer when the heat just wasn't there!
Member Since: June 24, 2007 Posts: 0 Comments: 1498
##### 1108. Astrometeor
 Quoting 1106. cyclonebuster:Is Google building some Tunnels? Link...I heard one rumor that it could be a data center. Lots of computers put together in one spot need a way to cool off, and apparently one of the best ways is to use water, a barge, and some piping and do a transfer of heat similar to what nuke plants do.
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##### 1107. TropicalAnalystwx13
 Quoting 1062. JohnLonergan: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.Quoting 1065. ScottLincoln: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!Quoting 1069. FLwolverine: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.Quoting 1077. Birthmark: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!Quoting 1101. Xulonn: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.Thanks everyone!
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