"Philip Eden" philipATweatherHYPHENukDOTcom wrote in message
...
Have a look at
http://www.climate-uk.com/temp.htm
There is a marked periodicity in the top (10-day mean)
chart, especially in the westerly index. In previous years
periodicities have come and gone pretty quickly, and I can't
remember seeing one quite as marked as this. It's not a
statistical artifact ... it's easy to remember the westerly
spells in early Jan, early Feb, mid-Mar, early to mid
April, and late May, and also the blocked spells
between.

Philip Eden

A 30-35 day oscillation has been reported in the literature in association
with N Atlantic sector blocking and retrogression of the jet,this may be a
harmonic of a 70 day signal.
Causes may be an internal oscillation involving barotropic interaction with
topography,probably unlikely in the Atlantic,or interaction of synoptic
transients with the mean flow.I'll find some references if you're
interested,

--
regards,
David

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