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For those wondering what causes a Sudden Stratospheric Warming (Small,
Medium or Intermediate, and Large) the possible source & knock on effects to
global circulations, you may wish to read the following link.

http://neven1.typepad.com/blog/2013/...s-effects.html

Here is an extract, but please read the whole article that indicates that
the source of most Sudden Stratospheric Warmings in the Northern Hemisphere
can be traced back to the The Taklamakan Desert, Kunlun Shan & Altun
Mountains in Asia.

When a large SSW event occurs such as we had in 2013, warm and descending
air over the pole compresses even more, warms even more, disrupts the vortex
(as shown above) and turns the AO Index negative. What needs to be clear
however is that the AO Index is of course a tropospheric reading, and the
SSW begins in the stratosphere and the pressure effects can work their way
down into the troposphere and last over a period of many weeks.

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Thanks David, skimmed through the blog earlier. Now justifies a more careful
reading. One thing missing (unless I missed it) was a reference to breaking
Rossby waves. Of course it could be the mountains that help trigger Rossby
wave breaking. Food for thought, and I'll make sure that some of my ex
colleagues see this too.

All the very best,
Will
--
http://www.lyneside.demon.co.uk/Hayt...antage_Pro.htm
Will Hand (Haytor, Devon, 1017 feet asl)
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