Re: EOF signs

To add a bit more information:

Consider EOF(neof,lat,lon) and you want the
first EOF over (say) Iceland to be negative

    if (EOF(0,{64},{340}).gt.0) then
        EOF(0,:,:) = -EOF(0,:,:) ; switch all signs
    end if

Wei Huang wrote:
> Aideen,
>
> There is no way to have the EOFs automatically
> give the same sign. The EOFs are calculated using
> LAPACK's "dspevx" routine.
>
> If there is a location in space that you want a
> particular sign, you could test that point and
> change the sign accordingly.
>
> Regards,
>
> Wei Huang
> huangwei_at_ucar.edu <mailto:huangwei_at_ucar.edu>
> VETS/CISL
> National Center for Atmospheric Research
> P.O. Box 3000 (1850 Table Mesa Dr.)
> Boulder, CO 80307-3000 USA
> (303) 497-8924
>
>
>
>
>
> On Sep 9, 2009, at 7:44 AM, Aideen Foley wrote:
>
>> Hello.
>> I am applying the same EOF analysis script to output from different
>> climate models, and finding that for some datasets, the primary EOF is
>> positive, and for others it is negative, with a time amplitude series
>> that is the inverse of what I would expect were it positive. I know
>> that that one can multiply the EOF and it's time amplitude series by
>> -1 to aid interpretation, but I would like to understand why the
>> eofunc routine prefers inverted output for some of my data but not for
>> others. I would like if it followed the same convention with each.
>> dataset. Can anyone help me with this question?
>> Many thanks,
>> Aideen Foley
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>
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Received on Wed Sep 09 2009 - 09:19:14 MDT