Re: EOF NAO different sign convention?

Thank you very much to both. I was imagining this was the reason, but I
couldnt find the answer in the documentation.

But also, this helped me see that some of my data are wrong,

Thank you very much indeed,

Simone

On Wednesday 08 August 2007 17:40, Dennis Shea wrote:
> As noted by Mike Notaro, the sign convention is
> completely arbitrary. EOFs are as returned from LAPACK.
> As noted in the documentation:
>
> "The results may produce patterns that are similar to physical modes
> within the the system. However, the procedure is strictly mathematical
> (not statistical) and is not based upon physics."
>
> Simone Marras wrote:
> > Good morning everyone,
> >
> > I was starting to use the eof_1.ncl function from
> > http://www.ncl.ucar.edu/Applications/eof.shtml
> >
> > with some WACCM and ERA40 products; I am a little surprised in finding
> > that the sign for the NAO SLP patterns seem to be opposite to the
> > standard usually found in EOF outputs (I computed the EOF for DJF and
> > JJA).
> >
> > I would expect negative region on the top and positive on the bottom
> > instead of the other way around.
> >
> > Am I misunderstanding anything? Is there any sign convention that are
> > being used in the NCL eof_1.ncl function?
> >
> > Thanks in advance
> >
> > Simone
> > _______________________________________________
> > ncl-talk mailing list
> > ncl-talk_at_ucar.edu
> > http://mailman.ucar.edu/mailman/listinfo/ncl-talk

-- 
Simone Marras, Ph.D. Student
BSC & Universitat Politecnica de Catalunya
Jordi Jirona 29
08034 Barcelona
Spain
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