# Barriers in the Atmosphere: Arctic Oscillation (3)

By: Dr. Ricky Rood , 12:50 AM GMT on October 03, 2013

Barriers in the Atmosphere: Arctic Oscillation (3)

I want to continue with the Arctic Oscillation / North Atlantic Oscillation. First, however, here is the link to my August presentation. Also here is a link to the GLISAclimate.org project workspace where I collected together the materials I used in the presentation - Arctic Oscillation: Climate variability in the Great Lakes.

Here are the previous entries in the series:
Behavior
Definitions and Some Background

This blog is mostly a setup for the next one. (And yes I did notice that the IPCC AR-5 report was released, but I don’t have anything different to say about it than many of my more able colleagues. I’ll get to it.)

In the talk that I linked to above, I used a couple of diagrams that the audience told me worked very well. I am going to try them out in this blog. In the previous blogs I used the CPC Climate Glossary to give the definition of the Arctic Oscillation. “The Arctic Oscillation is a pattern in which atmospheric pressure at polar and middle latitudes fluctuates between negative and positive phases.” This definition does not really do much for me. It’s one of those definitions that I imagine if I ask 10 atmospheric scientists to tell me what it means, I will get 12 answers. Therefore, I will draw a picture.

Figure 1: Adapted from Jim Hurrell – This picture is a schematic representation of the positive and negative phases of the Arctic Oscillation. In the positive phase the pressure is low at the pole and high at middle latitudes. This is the positive phase because if you calculate the difference between middle and high latitudes it is large. In the negative phase the pressure is not as low at the pole and not as high at middle latitudes. This is the negative phase because if you calculate the difference between middle and high latitudes it is small. The refrigerator suggests that this is like opening and closing the refrigerator door (see Behavior).

This figure helps me with the definition. I want to focus on the low pressure at high latitudes, which in this figure is drawn idealistically at the pole. In reality, it is likely to wander off the pole, a fact that will be important in the next blog. When the pressure is low at the pole, then there is a stronger vortex of air circulating around the pole. When the pressure at the pole is not as low, then there is a weaker vortex. In both cases, strong or weak vortex, the air generally moves from west to east.

For clarity, vorticity is a parameter that describes rotation in a fluid. A vortex is a feature in a fluid dominated by vorticity – that is it is rotationally dominated. Tornadoes and hurricanes are weather features that we often call vortices; there is an obvious circulation of air in these features. In the Earth’s atmosphere at middle and high latitudes rotation is an important characteristic of the flow, due to the rotation of the Earth. The reason air moves in the west to east direction for both the weak and strong vortex cases of Figure 1 is that the rotation of the Earth is important to the flow.

In Figure 2 I have set up an even more idealized figure. I also provide this link to a Powerpoint animation, that I am not smart enough to incorporate into the blog. In the animation I have five slides that clarify the point that I make in Figure 2.

Figure 2: A vortex and a ball. In the center of the figure is low pressure, meant to be an analogue to the vortex over the pole in Figure 1. Parcels of air move around the low pressure system. If it takes the same amount of time for a parcel farther away from the low pressure center to go around the vortex as a parcel nearer the center, then the parcel farther away has to go faster because the distance it has to go is longer. That is why I drew that arrow, saying that air moves “faster” at the outside edge of the vortex.

To set my point a little more, imagine you are on a bridge overlooking a running stream. If you drop a stick in the water near the edge where the water is moving slowly, then if the stick drifts towards the more rapidly flowing water, it is carried downstream at the edge of the fast moving water. It does not cross the core of fast moving water – this jet of water. In fact the jet is something of a barrier that keeps material from crossing the stream. Material is transported downstream.

Back to Figure 2: Imagine that you want to roll a ball into the center of a vortex. As the ball gets to the edge it gets caught up in the flow and pulled around the edge. It does not roll into the center. Look at the this link to a Powerpoint animation to get a better idea of what’s going on.

Now go back to Figure 1. The vortex in Figure 1 is also a barrier. The southern edge of vortex is a jet stream. Air on the two sides of the vortex often has different characteristics. Intuitively, there is colder air on the poleward side. 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 air on one side is largely separated from the air on the other side. In the next blog, I will describe the difference between the strong and the weak case and its relevance to weather, climate and, perhaps, climate change.

r

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##### 20. Some1Has2BtheRookie
 Your blog topic is an interesting read, Ricky. I look forward to your expansion on this in the next blog.
##### 19. cyclonebuster
 Let's vote is it a Volleyball a Soccer ball or a box?
##### 18. RickyRood
 And even worse it's in the NPS talk and the animation ... got to get my editor (sister) back in the mix.before long I'll be saying there's no their there or want no what to where when I'm there I'm not even very good at being clever ... Quoting 10. Patrap:Me tinks maybe datz a "spelling" error on the Image.It's "Ball"We dont get to say dat un here everyday.; )
##### 16. cyclonebuster
 Quoting 13. RickyRood:That's worse that a spelling error ... It's old man trying to do too many things cognitive slippage. That's how you end up at Dallas instead of Dulles ...Will change (after class).r I think the good Dr. is very tired... "than" not "that"....
##### 15. cyclonebuster
 Quoting 9. SteveDa1:I don't get it either.It must be a typo; I think they meant ball.Specifically a soccer ball I think... Anyways I get what the good Dr. meant and know what he was trying to convey though his example...
##### 14. barbamz
 Thank you for the comprehensive explanations and graphics, Dr. Rood; very appreciated. And those penguins in the powerpoint file really made my smile :)Link
Member Since: October 25, 2008 Posts: 75 Comments: 8920
##### 13. RickyRood
 That's worse that a spelling error ... It's old man trying to do too many things cognitive slippage. That's how you end up at Dallas instead of Dulles ...Will change (after class).rQuoting 10. Patrap:Me tinks maybe datz a "spelling" error on the Image.It's "Ball"We dont get to say dat un here everyday.; )
##### 12. JohnLonergan
 Oops, The State of the Oceans Report I posted at #8 is the 2011 version, here is the 2013 Report:Executive Summary• Climate change and the ocean – What does the future hold?The ocean is shielding us from the worst effects of accelerating climate change by absorbing excess CO2 and heat from the atmosphere. The twin effects of this – acidification and ocean warming – are combining with increased levels of deoxygenation, caused by nutrient run-off from agriculture near the coast ,and by climate change offshore, to produce what has become known as the ocean’s ‘deadly trio’ of threats whose impacts are potentially far greater because of the interaction of one on another. The scale and rate of this change is unprecedented in Earth’s known history and is exposing organisms to intolerable and unpredictable evolutionary pressure.• Climate change impacts on coral reefsSynergies with local effects, possibilities for acclimation, and management implications Coral reefs are extremely vulnerable to the impacts of climate change. It is imperative and urgent that emissions targets below 450 ppm CO2e be agreed and implemented, combined with coordinated programmes at local and regional levels to reduce other stress factors and boost resilience; otherwise it is predicted that most reefs will be lost as effective, productive systems within a few decades.• Fisheries: Hope or despair?The global picture of ongoing depletions of fish stocks, the degradation of food webs, threats to seafood security and poor quality of most fishing management is alarming and demonstrates that recent more optimistic outlooks aremisplaced. Reversing these global trends towards “despair” demands urgent, focused, innovative action to promote effective community- and ecosystem-based management.• Evaluating legacy contaminants and emerging chemicals in marine environments.Protecting marine ecosystems and seafood resources from the adverse effects of complex cocktails of ‘legacy’ (already regulated) contaminants, emerging (unregulated) chemicals and natural chemicals (e.g. algal biotoxins) remains a critical, unresolved global problem. The economic and infrastructural challenges posed by such a wide variety of chemicals means that the most cost-effective approach is to implement a targeted, effects-based strategy that prioritizes key groups of chemicals of most concern.• Ocean in peril: Reforming the management of global ocean living resources in areas beyond national jurisdictionThe current system of high seas governance is fraught with gaps, directly leading to themismanagement and misappropriation of living resources, and placing our ocean in peril. It is time for a new paradigm that can only come about through the fundamental reform of existing organisations and systems, overseen by a new global infrastructure to coordinate and enforce the necessary action. Crucially, the authors call for the negotiation of a new implementing agreement for the conservation and sustainable use of biodiversity in areas beyond national jurisdiction.Concluding StatementFounded to investigate the impacts of anthropogenic stressors on the ocean and identify workable solutions to eliminate or remedy them, IPSO– with the support of IUCN – is unique in bringing together experts from a range of disciplines within marine science, as well as the legal, policy and communications arenas, in order to highlight the connectivity and synergy between the multiple stressors impacting the ocean and treat them collectively.This holistic approach is essential to developing viable, practical solutions that consider marine ecosystem health, socio-economic drivers, as well as the larger Earth system perspective. Achieving this integrated, ecosystem-based management of the ocean and its resources is an immensely complex challenge but these five papers all stress that we have a vast wealth of information, expertise, management tools and proven solutions at our disposal.The two IPSO workshops showed that deferring action will increase costs in the future and lead to even greater, perhaps irreversible, losses. If we want to continue to benefit from the goods and services the ocean has provided for millennia, we must radically change the way we view, value, use and govern marine ecosystemsAs a matter of urgency, IPSO urges that:• There should be a significant reduction in global C02 emissions to limit temperature rise to less than 2C or below 450 CO2e . Current targets for carbon emission reductions are insufficient in terms of ensuring coral reef survival, especially as there is a time lag of several decades between atmospheric CO2 and CO2 dissolved in the océan.• Effective implementation of community – and ecosystem-based management, favouring small-scale fisheries is achieved. Examples of broad-scale measures include introducing true co-management with resource adjacent communities, eliminating harmful subsidies that drive overcapacity, protection of vulnerable marine ecosystems, banning the most destructive fishing gear and combatting IUU fishing.• The global infrastructure for high seas governance should be enhanced so that it is fit-for-purpose. A global high seas enforcement agency should be established to provide integrated and coordinated monitoring and enforcement for the full range of threats to ocean sustainability and globalsecurity. Most importantly, a new implementing agreement for the conservation and sustainable use of biodiversity in areas beyond national jurisdiction under the auspices of UNCLOS should be introduced urgently.RelatedOcean acidification due to carbon emissions is at highest for 300m yearsOverfishing and pollution are part of the problem, scientists say, warning that mass extinction of species may be inevitable
Member Since: June 27, 2012 Posts: 0 Comments: 4410
 Re: Comment 8Right wing Republican think tank staffers working on ways to spin the death of the oceans:Jellyfish - its the new omega-3 source; *** Now with no Omega-3's ***Jellyfish - Yummy in the tummy (just watch those poisonous spines)Jellyfish - You'll wish you never ate tuna.
##### 10. Patrap
 Me tinks maybe datz a "spelling" error on the Image.It's "Ball"We dont get to say dat un here everyday.; )
##### 9. SteveDa1
 Quoting 6. cyclonebuster:Try to roll the box towards the vortex? How do you roll a box?I don't get it either.It must be a typo; I think they meant ball.
##### 8. JohnLonergan
 MULTIPLE OCEAN STRESSES THREATEN "GLOBALLY SIGNIFICANT" MARINE EXTINCTIONA high-level international workshop convened by IPSO met at the University of Oxford earlier this year. It was the first inter-disciplinary international meeting of marine scientists of its kind and was designed to consider the cumulative impact of multiple stressors on the ocean, including warming, acidification, and overfishing.The 3 day workshop, co-sponsored by the International Union for Conservation of Nature (IUCN), looked at the latest science across different disciplines.The 27 participants from 18 organisations in 6 countries produced a grave assessment of current threats — and a stark conclusion about future risks to marine and human life if the current trajectory of damage continues: that the world's ocean is at high risk of entering a phase of extinction of marine species unprecedented in human history.Delegates called for urgent and unequivocal action to halt further declines in ocean health. (click for press release)The report summary (released 21 June 2011) outlines the main findings and recommendations. The full report will be released at a later date.Title: Rogers, A.D. & Laffoley, D.d'A. 2011. International Earth system expert workshop on ocean stresses and impacts. Summary report. IPSO Oxford, 18 pp. For a full list of participants, please see table at the end of the long version.Report Summary: long version / shorter version.The report is also accompanied by four case studies, which look in more detail at some of the workshop's main findings.Case Study 1: The potentially deadly trio of factors — warming, acidification and anoxia — affecting today's oceans, by Professor Jelle Bijma, Marine Biogeosciences, Alfred Wegener Institute for Polar and Marine Research. Watch his explanation, beginning with the growing problem of anoxia, or dead zones, in the ocean.Case Study 2: End of paradise: Coral reefs facing multiple attacks, by Ove Hoegh-Guldberg , Director, Global Change Institute, University of QueenslandIn Brief: What the multi-disciplinary approach of the IPSO workshop made clear for the first time was the multiple threats reefs are facing, that are now acting together to have a greater impact than if they were occurring on their own.Link to PDFThis suggests that existing scientific projections of how coral reefs will respond to global warming have been highly conservative and must now be modified.Case Study 3: Pollution and Marine Species: new challenges of an old problem by Professor Tom Hutchinson, Centre for Environment, Fisheries & Aquaculture Science (CEFAS)Link to videon Brief: Continued releases and slow breakdown rates mean that legacy chemical pollution ( such as from DDT) remains a major concern. However, concerns have been raised recently over a wide range of novel chemicals now being found in marine ecosystems or suspected to be harmful to marine life. High-profile examples include brominated flame retardants, fluorinated compounds, pharmaceuticals and synthetic musks used in detergents and personal care products.Some of these chemicals have been located recently in the Canadian Arctic seas, and some are known to be endocrine disrupters or can damage immune systems. Marine litter and plastics are also of major concern, and there is evidence that certain plastics can transport other harmful chemicals in the marine environment.Download Case Study PDFCase Study 4: Vanishing Resource: The Tale of the Chinese Bahaba by Dr William Cheung, Lecturer in Marine Ecosystem Services, School of Environmental Sciences at the University of East AngliaIn Brief: Scientists at the IPSO meeting agreed that overfishing is exerting an intolerable pressure on ecosystems already under attack by the effects of acidification and warming, and other largely man-made ocean problems. A recent study showed that 63% of the assessed fish stocks worldwide are over-exploited or depleted and over half of them require further reduction of fishing, in order to recover.The near extinction of a fish called Chinese bahaba (Bahaba taipingensis) is one of the many examples that highlight how overfishing threatens marine biodiversity. It has taken less than seventy years for this giant fish to become critically endangered after it was first described by scientists in the 1930s.Download Case Study PDF
Member Since: June 27, 2012 Posts: 0 Comments: 4410
##### 7. Xandra
 Glaciologist Aslak Grinsted says the IPCC are too optimistic and over-confident in their ice-sheet predictions and that the ice sheet experts are actually more pessimistic.Optimistic & over-confident ice sheet projections in AR5 "AR5 process based model projections are much more conservative/optimistic and has much more narrow uncertainties than the ice sheet experts (Fig.1). There can be no good reason for why the AR5 authors have much greater confidence in their ability to project ice sheet loss than ice sheet experts themselves. Notably the best guess view of ice sheet experts nearly falls outside the AR5 process based range. The worst case scenario from ice sheet experts is more than 60 cm higher than the worst case from the AR5 process models."Figure 1: Projections of ice sheet mass loss over the 21st century under RCP4.5. The AR5 process based projections appear optimistic and over confident when compared with views of ice sheet experts.More from Aslak Grinsted:AR5 sea level rise uncertainty communication failure "I am disappointed in how the sea level rise projection uncertainties are presented in the IPCC AR5. The way the numbers are presented makes people believe 98 cm by 2100 is a worst-case scenario which it clearly isn't. The AR5 does have caveats which explains why it could be more, but unfortunately this is buried in language that clearly goes over the heads of most people."
##### 6. cyclonebuster
 Try to roll the box towards the vortex? How do you roll a box?
##### 5. BaltimoreBrian
 Quoting 2. Astrometeor:Thanks for the set-up Dr. Rood, looking forward to the next blog sir!I feel as if Brian was tuned in with your new posting Doc, he plussed it before my computer could even load the blog...lol.Face it astro. I'm just older and faster ;)
##### 4. BaltimoreBrian
 This article just came up and it is important enough that I am adding it now.!!! How to detect pseudo-science B.S.
##### 3. RevElvis
 The Story of Solutions The Story of Solutions explores how we can move our economy in a more sustainable and just direction, starting with orienting ourselves toward a new goal.In the current 'Game of More', we're told to cheer a growing economy – more roads, more malls, more Stuff! – even though our health indicators are worsening, income inequality is growing and polar icecaps are melting. But what if we changed the point of the game? What if the goal of our economy wasn't more, but better – better health, better jobs and a better chance to survive on the planet?Truth-Out.org
##### 2. Astrometeor
 Thanks for the set-up Dr. Rood, looking forward to the next blog sir!I feel as if Brian was tuned in with your new posting Doc, he plussed it before my computer could even load the blog...lol.

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### Dr. Ricky Rood's Climate Change Blog

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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