Re: EOF: PC normalization

Since PCs have variance equal to their eigenvalues, you could just divide
the "pseudo PC" by the its standard deviation (square-root of variance) to
get a "pseudo PC" scaled to unit variance. Is that what you want? If you
want it to have zero mean then you can always just subtract the mean.

Andrew

On 18 May 2012 20:42, Torben Mueller <torbenmllr@aol.com> wrote:

> Dear NCL community,
>
> I have the following problem:
>
> I have two similar data sets (dataA and dataB).
> I calculate an EOF pattern from dataA:
>
> eof = eofcov_Wrap(dataA,neof)
>
> And then search for this EOF pattern in the dataB set, hence getting a
> "pseudo PC":
>
> eof_ts = eofcov_ts_Wrap(dataB,eof)
>
> The question is how to normalize the resulting PC to get zero mean and
> unit variance?
>
> Obviously I can not use the original eigenvalue associated with the
> eof pattern, e.g.:
>
> pcnorm = eof_ts(0,:)/sqrt(eof@eval(0))
>
> As the magnitude of the EOF pattern is different in dataB compared to
> dataA.
> Does anyone have a suggestion on how to approach this?
>
> Thanks!
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-- 
Dr Andrew Dawson
Atmospheric, Oceanic & Planetary Physics
Clarendon Laboratory
Parks Road
Oxford OX1 3PU, UK
Tel: +44 (0)1865 282438
Email: dawson@atm.ox.ac.uk
Web Site: http://www2.physics.ox.ac.uk/contacts/people/dawson

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Received on Thu May 24 01:52:30 2012