Interesting report on variablity of Jet Stream.

[elagache]

Dear WeatherCat climate watchers,

There was a report this morning on a study published once more in the journal Nature Climate Change.  You can read more about in this news article:

http://www.eenews.net/stories/1060001743

If you are so bold, you can even look at the abstract on the Nature Climate Change website itself:

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2271.html

The gist is that it appears that the Jet Stream has been altering its behavior and becoming more variable in its trajectory and energy.  As this happens, atmospheric flows are shifted as the Jet Stream passes over parts of the earth not normally exposed to Jet winds.  As the popular piece notes, the reason for the drought in California and the extreme cold in the eastern 2/3s of the United States is the same.  The Jet Stream made an unusual northernly arc that bought warm Pacific air into Alaska.  As a result, Alaska had an usually mild winter.  With the Jet Stream going into Alaska, California and the rest of the west got drought.  After passing far to the north, the Jet then plunged into the eastern part of the United States.  Having passed unusually far north, the air has been cooled by ice flows that normally do not have Jet Stream winds pass over them.  As a result, the air coming down into the United States was unusually cold - causing the miserable winter conditions many forum members suffered through.

This paper provides an explanation for the enigma presented by the paper I cited in this previous thread:

http://athena.trixology.com/index.php?topic=1296.0

So long as the Jet Stream continued in its traditional paths, the winters were indeed becoming milder as Dr James Screen from the University of Exeter reported.  However, if the Jet Stream changed its trajectory, it would encounter more "virgin" ice conditions and could once more bring very cold winters.

Interestingly enough, this idea of the Jet Stream shifting is controversial according to the popular piece.  It does nonetheless make good intuitive sense.

Cheers, Edouard 

[Blicj11]

Edouard:

Thanks for sharing. I always enjoy reading what you post on general weather topics, as well as what you say when you defend your position from time to time. 

[elagache]

Dear Blick and WeatherCat armchair physicists,

Thanks for sharing. I always enjoy reading what you post on general weather topics, as well as what you say when you defend your position from time to time. 

Thanks, it's tough to be sidelined academic.  Just become I no longer am able to teach college level courses doesn't mean I stopped pondering all these issues.

It is also interesting to ponder the physics associated with the atmosphere.  There was a BBC documentary about 10 years ago trying to describe the overall research on climate and there is a problem that really hits the nail on the head.  The climate on earth has been relatively stable for billions of years.  A theory was needed that balanced all the sources of energy and resulted in stability.  After trying to take into account of everything, they ran into a snag. 

The sun is maturing and as it does, it becomes more efficient in its nuclear fusion.  Over the past billion years or so, the sun's output has increased by 40%.  That should be more than enough to throw a monkey wrench into the climatic heat equations.  The current thinking is that plants used that additional energy and thus stabilized the climate were no other factor could.  I don't know how agriculture is factored into current climate models, but I do know this - I sure wouldn't what to figure all this out for myself!!

Cheers, Edouard