Re: EOF signs

Thank you both for your responses.
It is useful to know how this point testing can be accomplished, but for my
purposes it is not ideal. For comparative purposes I would prefer to apply
the same methodology to all datasets rather than adjusting some and not
others.
If you have any further thoughts on the matter, please let me know.
Regards,
Aideen

On Wed, Sep 9, 2009 at 4:19 PM, Dennis Shea <shea_at_ucar.edu> wrote:

> 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 Fri Sep 11 2009 - 05:53:50 MDT