[gradsusr] Fw: EOF and spectral analysis on GrADS

[tcavazos at cicese.mx]

Hi,

Yes, there is a script in Grads to obtain EOFs (PCA), I think it is from
Brian Coty (?), but I do not have the information here. I installed it in
one of my computers like ten 10 ago... But I am not aware of spectral
analysis on Grads.

Tereza

> Dear Tamer Nada
>
> Thank you by your explanation and suggestions. They were clear.
>
> By the way do you know where can I found the fortran subroutines from
> lepak library you commented?
>
>
> Thanks in advance
>
> Enviado via iPad
>
> Em 26/01/2013, Ã s 16:53, Tamer Nada <tamer540 at gmail.com> escreveu:
>
>> Dear :- Jose Augusto Paixão Veiga
>>
>> In Fortran :-
>>
>> You must know there is about 3 methods ( algorithms )  to calculate
>> eigen Vector and eigen Value  each method some of it efficient but just
>> compute only first Eigen value and first Eigen vector by suggest value
>> and using iteration methods to compute it until reach to the difference
>> between old value from last iteration to new value equal small fraction
>> you can determine it . another to methods using "SVD "  and this method
>> its divided by to relative to the shap of data matrix   and some of it
>> efficient but slow and some fast and not efficient
>>
>> I suggest to you to use lepak library in fortran ( its easy to call
>> subroutine ) or using high level language or statistical or climatic
>> package like NCL or R or Matlab
>>
>> On Sat, Jan 26, 2013 at 9:56 PM, Jose Augusto Paixão Veiga
>> <veiga.uea at gmail.com> wrote:
>>> Dear EOF expertise,
>>>
>>> one of you would have a material given instruction (if possible step by
>>> step) on how to calculate EOF?
>>>
>>> I would like to do a fortran program, from the initial point (for
>>> example: 1-read a 3-d matrix data, 2-calculate its inversion,
>>> 3-multiply it by its ....), to calculate EOF for climate study
>>> purposes.
>>>
>>> A flux diagram will be very appreciated.
>>>
>>> Thanks in advance.
>>>
>>> Augusto
>>>
>>>
>>> On Jan 26, 2013, at 3:41 PM, Tamer Nada <tamer540 at gmail.com> wrote:
>>>
>>>> on Grads No, but you can use NCL  or R to compute EOF; and Only R  or
>>>> Matlab to Compute CCA ,But also you can Use NCL to compute "SVD" and
>>>> after that you can compute CCA ,actually NCL have function to compute
>>>> CCA ,But not efficient because  its use old IBM Fortran subroutine ,so
>>>> its not work fine with big array of data and may be hang in
>>>> calculation ,so i prefer to use SVD function and after that you can
>>>> compute CCA
>>>>
>>>> On Sat, Jan 26, 2013 at 9:58 AM, ugo okoro <uknac23 at yahoo.com> wrote:
>>>>>
>>>>> Dear all,
>>>>>
>>>>> Please any info on how to run EOF and spectral analysis
>>>>> (frequency-time) on GrADS?
>>>>>
>>>>> Anticipating prompt response.
>>>>>
>>>>> Thanks.
>>>>>
>>>>> Ugo Okoro.
>>>>> CMSR-IAP
>>>>> CAS, Beijing.
>>>>>
>>>>> _______________________________________________
>>>>> gradsusr mailing list
>>>>> gradsusr at gradsusr.org
>>>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>>
>>>>
>>>>
>>>> --
>>>> =====================
>>>> Tamer Ali Nada
>>>> Research Worker
>>>> Cairo Numerical Weather Prediction Center { CNWP}
>>>> Egyption Meteorological Authority   { EMA }
>>>> Cairo , Egypt
>>>> ============================
>>>> tamer540 at yahoo.com
>>>> tamer540 at gmail.com
>>>> tamer.nada at noaa.gov
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>>>
>>>
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>>
>>
>>
>> --
>> =====================
>> Tamer Ali Nada
>> Research Worker
>> Cairo Numerical Weather Prediction Center { CNWP}
>> Egyption Meteorological Authority   { EMA }
>> Cairo , Egypt
>> ============================
>> tamer540 at yahoo.com
>> tamer540 at gmail.com
>> tamer.nada at noaa.gov
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-- 
Tereza Cavazos
Departamento de Oceanografia Fisica
CICESE
Ensenada, Baja California, MEXICO
http://usuario.cicese.mx/~tcavazos/