Mike and others,
This is a follow-up to my posting yesterday regarding eof_varimax. In
that I described an empirical procedure to calculate percentage variance
of rotated EOFs. I am afraid that procedure is not right, due to the
loss of orthogonality (space or time) after rotation of EOFs. So, please
disregard that message.
Saji N. Hameed, Assistant Researcher,
IPRC-SOEST, 2525 Correa Road, Univ. of Hawaii,
Honolulu, HI 96822, U.S.A
tel.: (808) 956 9534 , fax.: (808) 956 9425
> Today's Topics:
> 1. Re: ncl-talk Digest, Vol 16, eofunc_varimax (Saji Hameed)
> 2. accounting for surface area differences when averaging
> (Cathryn Meyer)
> 3. Re: accounting for surface area differences when averaging
> (Adam Phillips)
> Message: 1
> Date: Thu, 17 Mar 2005 10:58:38 -1000
> From: Saji Hameed <firstname.lastname@example.org>
> Subject: Re: ncl-talk Digest, Vol 16, eofunc_varimax
> To: email@example.com
> Message-ID: <firstname.lastname@example.org>
> Content-Type: text/plain; charset=us-ascii
> Jing has given you part of the answer. I will try to fill up what she
> has not mentioned.
> I have not tried this, but i have no reason to believe why it
> should not
> 1. eofunc_ts should be able to return your time series after varimax
> rotation, the same way it does return the time series for the
> unrotatedeofs. I guess this function regresses (evec) on (data) to
> obtain the
> time series.
> 2. You can always calculate the percentage variance explained by a
> pattern once you have (evec) and its corresponding time series and of
> course the data.
> a- sum up the variance in the (data) over the same domain that
> you had specified to the eof- functions.
> b- calculate the variance associated with each (evec) pattern.
> To do this multiply evec with the time series, find the
> variance and sum it up over the domain
> c - (b/a)*100 is the percentage variance associated with each
> A grads script that can do varimax can be found at
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