The explanation for the polar vortex is correct in that it’s a consequence of a significant southerly meander in the Polar Jet Stream and this has opened the door to a mass of cold air flooding in from the Arctic.
The PJS circumnavigates the mid to high northerly latitudes and acts as a barrier, trapping cold Arctic air to the north of it. Currently it is much further south across the US than normal (possibly further south than has previously been known), this has pushed the previous air mass out of the way and replaced it with cold air.
The PJS is also moving at a highly accelerated rate and is bringing a rapid succession of weather systems to other parts of the world.
The points that Prof Francis makes are also correct in terms of Arctic warming feedbacks and disrupted weather but I think it’s too early at this stage to blame the disruption to the PJS on global warming.
There are three further jet streams and we don’t really know that much about any of them. We know the basics but there’s a lot still to be learned.
It had long been predicted that GW would impact upon the jet streams, that much isn’t disputed. It’s the hows, whens and whys that can’t be answered and as such I think it’s premature to claim that the current disruption is caused by global warming. Yes it will be a factor, but is it the sole or main cause?
<< I have to ask, what was Arctic sea ice extent in 1975? What was the temperature? How do both of those compare to today? >>
The annual average Arctic sea-ice extent for the whole of 1975 was 12,945,690km2, for 2013 it was 10,419,456km2.
http://arctic.atmos.uiuc.edu/SEAICE/
http://www.ijis.iarc.uaf.edu/en/home/sea...
I’ve submitted a data retrieval request for the hourly observations for the Arctic in 1975, once I’ve got those I can give you an exact figure. For now, looking at the NASA GISS record in graph format shows that in 1975 the average Arctic temp was about 0.2°C and in 2011 it was about 2.3°C.
http://thinkprogress.org/wp-content/uplo...
GW doesn't explain the jet stream. Otherwise every weather pattern on the face of the planet would be predictable now and into the unknown...doesn't make sense. You need at the minimum three thirty year trends to perform a (basic) climate trend to constitute any type of pattern...basic math. If you only used two it would fit alarmist scenarios. Where everything is standardized. I can't access the first link. But I haven't ever heard or read of any extreme weather event as being predictable with any validity as to predictability. If you or anyone else has a link to such, I would be honored to read it.
Having enough basic science skills. I know the gradients range from high to low, not the other way around.
Here is whata I understand.
The strength of our geomagnetic fields impacts, directly, the strength of the arctic jet stream. (True for all other jet streams as well.) The link between other jet streams and geomagnetic fields strengths have been known for a long time. Arctic and antarctic jet stream variations linked with geomagnetic fields strengths is a newer concept but with the work of a team of scientists from Russia and Poland, the relationship is becoming much better defined.
The earth's geomagnetic fields fluctuate in strength over time and are directly linked, through induction I beleive, with the strength of the IMF (PossiblY EMF) The Magnatic Flux Field strength from the sun. IMF uis the interplanetary Magnetic Flux and I beleive that is the o0ne that impacts the earth's geomagnetic fields. This correltaion has been well known for a century or more.
Right now the EMF and related IMF are losing stength. See the Variable solar Dynamo paper for a great deal more detail. This paper and its conclusions were inependatly verified by the National Solar Observatory, NASA's Jet propultion laboratory and the Air Force Research Lab.
http://www.cdejager.com/wp-content/uploa...
http://www.space.com/11960-fading-sunspo...
From this the Earth's geomagnetic fields are losing strength and the Arctic jet stream is no longer strong enough to contain the arctic air mass. A team of Russian and Polish Physicists have been accuraely predicting weather patterns up to 6 months or more in adance by watching these relations ships and YES they accurately predicted this one as well. so, I don't have that link.
So to summarize my answer to your quesitons. Weaker solar magnetic flux fields leading to weaker geomagnetic fields has resulted in a weaker arctic jets streams and thus this abnormally cold weather event.
I hope you find this useful.
Well it is winter and this sometimes happens. As to the cold, this was quite common in the late 70s and early 80s
The vortex doesn't as a rule go this far south. I suspect the ice melt has altered conditions, and it is AGW moving the jet stream. Look at the snow that came through the middle east...yet another odd occurrence
Warm and cold, that is what was promised
It is like a woman. Unpredictable.
mother nature of course
To start, it appears that the southerly reach of the cold arctic air is a direct result of the jet stream location. So the question really is what causes the jet stream to meander south in a meridional pattern. The current thinking of course is that it is caused by global warming. Here, climate scientist Jennifer Frances explains:
2014: "Jennifer Francis, a research professor with Rutgers University’s Institute of Marine and Coastal Sciences, said that such extreme weather events can be caused by global warming. Despite the fact that the extreme weather is bitter cold in this case, warming of the arctic can have such an effect because it changes the flow of the jet stream. Sea ice melts, leaving more water surface area exposed to absorb sunlight, leading to further warming." http://www.usnews.com/opinion/articles/2014/01/06/is-global-warming-causing-the-polar-vortex
Yet, I recall the same argument made during the 70s when global cooling was an issue.
1975: "During cooler climatic periods, how-ever, the high-altitude winds are broken up into irregular cells by weaker and more plentiful pressure centers, causing formation of a "meridional circulation" pattern. These small, weak cells may stagnate over vast areas for many months, bringing unseasonably cold weather on one side and unseasonably warm weather on the other." http://www.sott.net/article/266751-1975-Science-News-Climate-change-Chilling-possibilities
And:
1974: "Paradoxically, the same vortex has created quite different weather quirks in the U.S. and other temperate zones. As the winds swirl around the globe, their southerly portions undulate like the bottom of a skirt (meridional circulation). Cold air is pulled down across the Western U.S. and warm air is swept up to the Northeast." http://www.perceptions.couk.com/cold-clim-fears.txt
I have to ask, what was Arctic sea ice extent in 1975? What was the temperature? How do both of those compare to today?
