Hi
I have one more question about rotated EOFs.
When i use the following loop to plot my rotated EOF with variance
explained, it is not working for variance explained of rotated EOF. For
example,
do n=0,2-1
res@gsnLeftString = "EOF "+(n+1)
*res@gsnRightString = sprintf("%5.1f", eof@pcvar(n)) +"%"*
plot(n)=gsn_csm_contour_map_polar(wks,ev_regres(n,:,:),res)
end do
gsn_panel(wks,plot,(/2,1/),resP) ; now draw as one plot
This (res@gsnRightString = sprintf("%5.1f", eof@pcvar(n)) +"%") is variance
explained by EOF instead of rotated EOF. When i modifiy this line by
res@gsnRightString = sprintf("%5.1f", ev_rot@pcvar(n)) +"%", it gives me
segmentation fault that pcvar is undefined variable or function. Here
ev_rot are my rotated EOFs.
Also, is there any difference between variance explained in EOF and rotated
EOFs?
Thanks in advance for help.
On Tue, Nov 6, 2012 at 4:49 PM, Dennis Shea <shea@ucar.edu> wrote:
> As noted in the eofunc_varimax documentation:
>
> "The results may be very dependent upon the user specified number of modes
> used in the rotation. The "best" number of modes to use may have to be
> determined by experiment."
>
> --
> Let's say the maximum possible number of eigenvalues/vectors is 1000.
> This means the 2nd EOF must be orthogonal to the 1st; the 3rd must
> be orthogonal to 1 and 2, etc. The orthogonality property impose
> constraints of the patterns.
>
> Even if you requested a subset of the eigen information, the LAPACK
> computes all the eigenvalues and returns just the subset but the
> full orthogonality is still in effect!
>
> If you use
> eof = eofunc(x,10, False)
> eofunc_varimax(eof)
>
> then the varimax imposes orthogonality on these 10 modes only.
>
> If you used only 2 modes .... then I'm not sure what you get
> but 2 modes in not 'right'
> eof = eofunc(x, 2, False)
> eofunc_varimax(eof)
>
>
>
>
>
>
> On 11/06/2012 03:00 PM, Waqar Younas wrote:
>
>> Hi Phillips
>> The data i used is NCEP/NCAP reanalysis of 500mb monthly geopotential
>> height from 1950-2000.
>> I got my results correct. The only confusion remaining is when i
>> calculate only 2 rotational components the results are not exact, but
>> when i calculate the 10 rotational components and plot only 2, the
>> results are more like NAO (first component) and PNA (second component).
>> Please find attached figure when i calculate 10 components and plot
>> first 2 components. The other figure (when i calculate only 2 components
>> and plot them) is attached in the first message above. I do not know why
>> there is such difference?
>>
>> Thanks.
>>
>>
>>
>> On Tue, Nov 6, 2012 at 1:29 PM, Adam Phillips <asphilli@ucar.edu
>> <mailto:asphilli@ucar.edu>> wrote:
>>
>> Hi Waqar,
>> Looking at your script, I don't see anything wrong. That leaves me
>> trying to answer why the patterns are not what you expected them to
>> be, and of course I cannot answer that. The patterns depend on the
>> data you use. You can try running your script on other data, say,
>> the NCEP/NCAR Reanalysis, to see if the results are what you expect.
>> Good luck,
>> Adam
>>
>>
>> On 11/6/12 12:31 PM, Waqar Younas wrote:
>>
>>> Hi
>>> It does not make any difference because even without reordering, i
>>> was getting the EOF patterns in order as first mode explained
>>> variance was 13.3% and second one is 10% and so on. The patterns
>>> did not change.
>>> I do not know where i am making mistake because especially for
>>> PNA, the most variance should be in Western side but my PNA
>>> pattern is capturing variability on Eastern side too. Now i am
>>> attaching the whole code which i modified using eof_4.ncl.
>>> Thanks.
>>>
>>>
>>>
>>>
>>>
>>> On Tue, Nov 6, 2012 at 9:05 AM, Dennis Shea <shea@ucar.edu
>>> <mailto:shea@ucar.edu>> wrote:
>>>
>>> The documentation for eofunc_varimax includes the following
>>>
>>> " The order of the returned varimax rotated EOFs is not
>>> necessarily in strict descending order as returned by eofunc
>>> or eofunc_varimax_Wrap. The user should use the
>>> *eofunc_varimax_reorder* procedure to place the returned
>>> varimax rotated EOFs into strict descending order."
>>>
>>> http://www.ncl.ucar.edu/**Document/Functions/**
>>> Contributed/eofunc_varimax_**reorder.shtml<http://www.ncl.ucar.edu/Document/Functions/Contributed/eofunc_varimax_reorder.shtml>
>>>
>>> It seems to me you should have"
>>>
>>> ev_rot = eofunc_varimax_Wrap(eof,1)
>>> printVarSummary(ev_rot)
>>>
>>> eofunc_varimax_reorder(ev_rot)
>>> printVarSummary(ev_rot)
>>>
>>> ; ev_rot will be orthogonal. However, 'ev_rot1'
>>> ; will not tield principal components that are independent
>>>
>>>
>>>
>>> ev_rot1 = eofunc_ts_Wrap (wx, ev_rot, optETS)
>>>
>>>
>>> On 11/05/2012 06:23 PM, Waqar Younas wrote:
>>>
>>> Hi all,
>>> I need help in performing the rotated EOF of NCEP/NCAR
>>> reanalysis data
>>> using NCL. I used the code eof_4.ncl present on ncl
>>> functions page. This
>>> code use the same data i.e. 500mb monthly data set from
>>> NCEP/NCAR from
>>> 20S to 90S but this code only calculates the EOF. This code
>>> is
>>> originally written for calculating AAO oscillations.
>>> For my case, i change the region from 20-90 N and for
>>> rotated EOF, i
>>> added these lines in the code
>>>
>>> ;;;;;;; Rotation of EOF
>>>
>>> ev_rot = eofunc_varimax_Wrap(eof,1)
>>> printVarSummary(ev_rot)
>>> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;**;;;;;;;;;;;;;;;;;;;;
>>> ev_rot1 = eofunc_ts_Wrap (wx, ev_rot, optETS)
>>> ev_rot1 = dim_standardize_n( ev_rot1, 0, 1)
>>> ;
>>> ==============================**
>>> ==============================**=====
>>> ; Regress
>>> ;
>>> ==============================**
>>> ==============================**=====
>>> ev_regres = ev_rot ;
>>> create an array w
>>> meta data
>>> do ne=0,neof-1
>>> ev_regres(ne,:,:) = (/ regCoef(ev_rot1(ne,:),
>>> xAnom(lat|:,lon|:,time|:)) /)
>>> end do
>>> At the end, i plot this ev_regres which contains REOF1 and
>>> REOF2.
>>> According to many papers and definitions of Climate
>>> prediction centre,
>>> the first REOF should be NAO and second should be PNA. In
>>> my case, the
>>> first EOF is NAO but it is slightly different. The second
>>> EOF is
>>> capturing PNA but it is not exact. I am attaching the figure.
>>> For my research i need PNA pattern which is second REOF.
>>> It is capturing
>>> PNA but also some other variabilties too.
>>> Thanks for the help in advance.
>>>
>>>
>>>
>>>
>>>
>>> --
>>> Best Regards
>>>
>>> Waqar Younas
>>> PhD Candidate
>>> Natural Resources and Environmental Studies (NRES)
>>> University of Northern British Columbia (UNBC)
>>> Canada
>>>
>>>
>>>
>>> ______________________________**_________________
>>> ncl-talk mailing list
>>> List instructions, subscriber options, unsubscribe:
>>> http://mailman.ucar.edu/**mailman/listinfo/ncl-talk<http://mailman.ucar.edu/mailman/listinfo/ncl-talk>
>>>
>>>
>>>
>>>
>>>
>>> --
>>> Best Regards
>>>
>>> Waqar Younas
>>> PhD Candidate
>>> Natural Resources and Environmental Studies (NRES)
>>> University of Northern British Columbia (UNBC)
>>> Canada
>>>
>>>
>>>
>>> ______________________________**_________________
>>> ncl-talk mailing list
>>> List instructions, subscriber options, unsubscribe:
>>> http://mailman.ucar.edu/**mailman/listinfo/ncl-talk<http://mailman.ucar.edu/mailman/listinfo/ncl-talk>
>>>
>>
>>
>> ______________________________**_________________
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>>
>>
>>
>>
>> --
>> Best Regards
>>
>> Waqar Younas
>> PhD Candidate
>> Natural Resources and Environmental Studies (NRES)
>> University of Northern British Columbia (UNBC)
>> Canada
>>
>>
>>
>> ______________________________**_________________
>> ncl-talk mailing list
>> List instructions, subscriber options, unsubscribe:
>> http://mailman.ucar.edu/**mailman/listinfo/ncl-talk<http://mailman.ucar.edu/mailman/listinfo/ncl-talk>
>>
>>
>
-- Best Regards Waqar Younas PhD Candidate Natural Resources and Environmental Studies (NRES) University of Northern British Columbia (UNBC) Canada
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Received on Thu Nov 8 20:10:36 2012
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