Wobbles in the Barriers: Arctic Oscillation (4)

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

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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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Quoting 1302. Neapolitan:
So in short, all the hyperventilating this week in the denialosphere about Lockwood's claim that lower solar activity means we're headed for another "little ice age" would be correct except for the fact that:

1) The "Little Ice Age" wasn't;
2) Lower solar activity, even to Maunder Minimum levels, won't be anywhere close to enough to compensate for increased CO2 concentrations;
3) The Maunder Minimum and the "Little Ice Age That Wasn't" (see #1) did not occur in sync with one another;
4) Lockwood implied no such thing;
5) The laws of physics would have to be overturned for another "Little Ice Age That Wasn't" (see #1) to occur because of the current lull in solar activity.

Okay: now cue McIntyre and Watts to weasel out of this one by claiming that Lockwood is a lying socialist who doesn't understand his own research as well as they do.

(On a related note, when can we expect a conciliatory note of apology from Cochise and/or iceagecoming?)


To answer your question, when "global cooling' hits Hades.
Member Since: June 27, 2012 Posts: 0 Comments: 4083
Quoting 1298. JohnLonergan:
Mike Lockwood responds to misrepresentation of science:

Solar Activity and the so-called “Little Ice Age”

I'm a professor of space environment physics and a director of research at the University of Reading in the UK. My particular topic of research is the sun, how it changes over time and how those changes affect the space environment, the weather and the climate on Earth.

In the last few years, my work has focused on how temperatures in the northern hemisphere have responded to periods in history when the sun has been very quiet. The "activity" of the sun's magnetic field is related to the number of sunspots that appear on its surface.

The sun's activity rises and falls on an approximately 11-year cycle, but also varies on century-long timescales. It's this research I talked to BBC weatherman Paul Hudson about in an interview for the BBC's Inside Out programme.

Unfortunately, I now find myself in the position of being cited as predicting that the current rapid decline in solar activity will plunge the world into a "Little Ice Age".

This is very disappointing as it is not at all supported by the science.

Read more at CarbonBrief >>
So in short, all the hyperventilating this week in the denialosphere about Lockwood's claim that lower solar activity means we're headed for another "little ice age" would be correct except for the fact that:

1) The "Little Ice Age" wasn't;
2) Lower solar activity, even to Maunder Minimum levels, won't be anywhere close to enough to compensate for increased CO2 concentrations;
3) The Maunder Minimum and the "Little Ice Age That Wasn't" (see #1) did not occur in sync with one another;
4) Lockwood implied no such thing;
5) The laws of physics would have to be overturned for another "Little Ice Age That Wasn't" (see #1) to occur because of the current lull in solar activity.

Okay: now cue McIntyre and Watts to weasel out of this one by claiming that Lockwood is a lying socialist who doesn't understand his own research as well as they do.

(On a related note, when can we expect a conciliatory note of apology from Cochise and/or iceagecoming?)
Member Since: November 8, 2009 Posts: 4 Comments: 14168
Quoting 1300. JohnLonergan:
Thanks, WU's handling of html leaves something to be desired.
True. But then again, whichever CMS The Carbon Brief is using should have been smart enough in the first place to omit the hard-to-handle quotation marks in the URL, or at least encode them...
Member Since: November 8, 2009 Posts: 4 Comments: 14168
Quoting 1299. FLwolverine:
#1298 - JohnL - the link didn't work because WU changed the quote marks " to a different symbol. Here's the correct link:

http://www.carbonbrief.org/blog/2013/11/solar-act ivity-and-the-so-called-“little-ice-age”/
Thanks, WU's handling of html leaves something to be desired.
Member Since: June 27, 2012 Posts: 0 Comments: 4083
#1298 - JohnL - the link didn't work because WU changed the quote marks " to a different symbol. Here's the correct link:

http://www.carbonbrief.org/blog/2013/11/solar-act ivity-and-the-so-called-“little-ice-age”/
Member Since: Posts: Comments:
Mike Lockwood responds to misrepresentation of science:

Solar Activity and the so-called “Little Ice Age”

I'm a professor of space environment physics and a director of research at the University of Reading in the UK. My particular topic of research is the sun, how it changes over time and how those changes affect the space environment, the weather and the climate on Earth.

In the last few years, my work has focused on how temperatures in the northern hemisphere have responded to periods in history when the sun has been very quiet. The "activity" of the sun's magnetic field is related to the number of sunspots that appear on its surface.

The sun's activity rises and falls on an approximately 11-year cycle, but also varies on century-long timescales. It's this research I talked to BBC weatherman Paul Hudson about in an interview for the BBC's Inside Out programme.

Unfortunately, I now find myself in the position of being cited as predicting that the current rapid decline in solar activity will plunge the world into a "Little Ice Age".

This is very disappointing as it is not at all supported by the science.

Read more at CarbonBrief >>
Member Since: June 27, 2012 Posts: 0 Comments: 4083
Quoting 1294. PensacolaDoug:




I'm not familiar with those. But I'm about to be. Thanks.
JAXA is theJapan Aerospace Exploration Agency. The data--the very widely-used data, I might add--are available to the public in several formats. The numbers I gave you came from a continually-updated text file found at http://www.ijis.iarc.uaf.edu/seaice/extent/plot_v 2.csv
Member Since: November 8, 2009 Posts: 4 Comments: 14168
.double post
Member Since: June 27, 2012 Posts: 0 Comments: 4083
To boldly go....






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Quoting 1292. Neapolitan:
I specifically stated IJIS/JAXA Arctic sea ice extent. If you're in need of more guidance than that, please let me know...




I'm not familiar with those. But I'm about to be. Thanks.
Member Since: Posts: Comments:
From Paul Krugman, a little trivia:

To Boldly Go, but Not to Blog
Busy day, not sure if I will manage to get anything up. But for your surreal pleasure: the US Navy has a brand-new super-high-tech ship, the Elmo Zumwalt — stealth, incredibly long-range weapons, etc.. And who is the new vessel’s captain?

Capt. James Kirk. I am not making this up.
Member Since: June 27, 2012 Posts: 0 Comments: 4083
Quoting 1289. PensacolaDoug:



Source your post. I'd like to see where you got that please.


Morning Pat.


BTW Fresca sucks.
I specifically stated IJIS/JAXA Arctic sea ice extent. If you're in need of more guidance than that, please let me know...
Member Since: November 8, 2009 Posts: 4 Comments: 14168
1291. yoboi
Quoting 1287. PensacolaDoug:
Speaking of Bastardi...







Joe Bastardi ‏@BigJoeBastardi 10m
Tom Nelson: Lewandowsky/Mann paper suggests that AGW is killin... http://tomnelson.blogspot.com/2013/11/lewandowskym ann-paper-suggests-that-agw.html?spref=tw …
IS this a joke? 1 author says he is in a war

Member Since: August 25, 2010 Posts: 8 Comments: 3071
Quoting 1286. Neapolitan:
For those who like to endlessly point out that there was more Arctic sea ice at this year's minimum than last, there's this little tidbit: over the last two weeks of October that just ended, IJIS/JAXA Arctic sea ice extent grew by 1.33 million km2. Over the same period last year, extent increased by 2.15 million km2. That means extent growth a year ago was 62% higher than it was over the same period this year.

Gee. See how much fun looking at short-term year-to-year statistics can be? And more importantly--and I'm certain this point will be completely lost on the Watts's and Bastardis and McIntyres of the world, along with all their run-to-every-science-blog-and-obediently-post-what ever-nonsense-we-tell-you-to followers--see how absolutely meaningless they can be?



Source your post. I'd like to see where you got that please.


Morning Pat.


BTW Fresca sucks.
Member Since: Posts: Comments:
Speaking of Bastardi...

Member Since: Posts: Comments:
For those who like to endlessly point out that there was more Arctic sea ice at this year's minimum than last, there's this little tidbit: over the last two weeks of October that just ended, IJIS/JAXA Arctic sea ice extent grew by 1.33 million km2. Over the same period last year, extent increased by 2.15 million km2. That means extent growth a year ago was 62% higher than it was over the same period this year.

Gee. See how much fun looking at short-term year-to-year statistics can be? And more importantly--and I'm certain this point will be completely lost on the Watts's and Bastardis and McIntyres of the world, along with all their run-to-every-science-blog-and-obediently-post-what ever-nonsense-we-tell-you-to followers--see how absolutely meaningless they can be?
Member Since: November 8, 2009 Posts: 4 Comments: 14168
Quoting 1284. JohnLonergan:
I excerpted this from HotWhopper this morning:

A plea for evidence - huh? What world does he inhabit?

How many times have you read a fake sceptic write something like what Paul Caruso writes:
...publish some verifiable empirical evidence that supports your argument...if you can persuade me that a 4/100th of a percent (sic) of the atmosphere is the control knob for the entire planet's temperature...

Of all the sciences I doubt there is any field of research in which more effort has gone into explaining it to all the myriad audiences. Even the least able like Paul Caruso.

How many times have you fallen for this sort of rhetoric and pointed the Paul Caruso's to an IPCC report, or to SkepticalScience.com or realclimate.org or to a basic description of how greenhouse gases work or to that excellent AGU video by Professor Richard Alley on carbon dioxide as the control knob? Only to have them reply "I don't believe it" or come back with the same inane request over and over again.

People like Paul Caruso are not interested in learning about science. They are too busy rejecting what they can't be bothered to learn and understand.
(my emphasis)

This describes our "drive by trolls" from last night perfectly, just replace "Paul Caruso" with the appropriate handle.


Ask Paul Caruso what percent of the atmosphere is that jacket you put on to keep you warmer on a cold day?
Member Since: January 2, 2006 Posts: 131 Comments: 20508
I excerpted this from HotWhopper this morning:

A plea for evidence - huh? What world does he inhabit?

How many times have you read a fake sceptic write something like what Paul Caruso writes:
...publish some verifiable empirical evidence that supports your argument...if you can persuade me that a 4/100th of a percent (sic) of the atmosphere is the control knob for the entire planet's temperature...

Of all the sciences I doubt there is any field of research in which more effort has gone into explaining it to all the myriad audiences. Even the least able like Paul Caruso.

How many times have you fallen for this sort of rhetoric and pointed the Paul Caruso's to an IPCC report, or to SkepticalScience.com or realclimate.org or to a basic description of how greenhouse gases work or to that excellent AGU video by Professor Richard Alley on carbon dioxide as the control knob? Only to have them reply "I don't believe it" or come back with the same inane request over and over again.

People like Paul Caruso are not interested in learning about science. They are too busy rejecting what they can't be bothered to learn and understand.
(my emphasis)

This describes our "drive by trolls" from last night perfectly, just replace "Paul Caruso" with the appropriate handle.
Member Since: June 27, 2012 Posts: 0 Comments: 4083
Earth needs Triage...
Member Since: January 2, 2006 Posts: 131 Comments: 20508
1282. nymore
I also wonder if someone will update their graph from something later than 2000, after all they seem to spend their whole day here.
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1281. nymore
Quoting 1275. Birthmark:

We're not changing the weather. We are changing the climate.
I like this comment, lets see if anyone can find the problem with it.

Hint. No I will not give one because it should be easy enough
Member Since: Posts: Comments:
post 1205 has 9 "likes" as proof.

This is a place for a particular kind of science and anything other than what is wanted to be seen or discussed is better taken elsewhere.

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this is the wrong blog to change viewpoints. you'd have better success trying to sell mopeds to a gang of Hell's Angels.

This blog is for AGW believers only. If you do not believe, you are not welcome here.



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Quoting 1275. Birthmark:

We're not changing the weather. We are changing the climate.
I don't think we are to a degree. Maybe 5% at most,I'll give you 5%. That's all.
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Quoting 1269. Daisyworld:


Just stop. You're being a climate troll.
You are being a sockpuppet troll! Ha Ha !
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Quoting 1267. Birthmark:

And what has that to do with anything -aside from turning a spotlight on your lack of familiarity of the topic?
I respect your stand. I think Humanity is heading in the wrong direction,but We have along way to go before we can change the weather.We need to focus on moral issues now! That will be our demise!
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1270. yoboi
Misinformation, disinformation and conflict



Link
Member Since: August 25, 2010 Posts: 8 Comments: 3071
Quoting 1265. Birthmark:

I mean this as gently as possible, but you really don't have the familiarity with this topic to even be posting. Go here and spend some time learning the topic. That should help you from making, well, idiotic posts that have no relevance on AGW/CC.
Funny,I guess I'm doomed to be a Denialist! Show me some real evidence. Is the equator breaking heat records?
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Quoting 1261. Birthmark:

Believe what? lol
That you prolly die! HYPOTHERMIA! Get's you everytime.
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Scientists can go back 800,000 years and get data ,BUT they can't go back before 1979 and get satellite data! HMMM!
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What if somebody dropped you off @ the northpole in January?Would you still believe?
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Quoting 1256. yoboi:



DR Spencer worked for NOAA & NASA......


And Snowden worked for the NSA. What's your point?
Member Since: January 11, 2012 Posts: 6 Comments: 908

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I'm a professor at U Michigan and lead a course on climate change problem solving. These articles often come from and contribute to the course.

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