[ncl-talk] Sum over a variable using several netcdf files

[Setareh Rahimi]

Dear Dennis,
I need sum!
Thanks  for your advice. It seems I have no way except using NCO or CDO. I
will try it.
Best wishes,

On Fri, Feb 18, 2022 at 10:53 PM Dennis Shea <shea at ucar.edu> wrote:

> "sum over all these 4 files to have a total temperature value"
>
> sum or average?
>
> =====================
>
>
>    diri = "./"
>    fili = systemfunc("cd "+diri+" ; ls FOO*.nc")
>    nfili= dimsizes(fili)
>    print("nfili="+nfili)
>    f    = addfiles(diri+fili,"r")
>    tmp  = f[:]->TEMP
>
>    printVarSummary(tmp)      ; tmp(time,lat,lon)
>                              ;       0   1   2
>
>    tavg = *dim_avg_n*_*Wrap* <https://www.ncl.ucar.edu/Document/Functions/Contributed/dim_avg_n_Wrap.shtml>(tmp,0)   ; _Wrap ==> return meta data
>
>    printVarSummary(tavg)     ; tavg(lat,lon)
>
> or
>
>    tsum = *dim_sum_n_Wrap* <https://www.ncl.ucar.edu/Document/Functions/Contributed/dim_sum_n_Wrap.shtml> (tmp,0)
>
>    printVarSummary(tsum)     ; tsum(lat,lon)
>
>  =============
>
> You could use the NCO or CDO from an NCL script.
>
> Use *systemfunc* <https://www.ncl.ucar.edu/Document/Functions/Built-in/systemfunc.shtml>
>
>     path = ....
>
>     systemfunc("...")   ; use CDO or NCO to create a file;; say  FOO_Avg.nc
>
>     favg = addfile("FOO_Avg.nc", r)  ; read the file created by NCO or CDO
>
>     tavg = favg->T...
>
>
> other examples are at:
>
> *https://www.ncl.ucar.edu/Applications/* <https://www.ncl.ucar.edu/Applications/>
>
> See under
>
> *Miscellaneous*
>
> *Specifically:  System interactions and scripting <https://www.ncl.ucar.edu/Applications/system.shtml>*
>
>
>
>
> *https://www.ncl.ucar.edu/Applications/system.shtml* <https://www.ncl.ucar.edu/Applications/system.shtml>
>
>
> On Fri, Feb 18, 2022 at 8:40 AM Setareh Rahimi via ncl-talk <
> ncl-talk at mailman.ucar.edu> wrote:
>
>> Dear Joe,
>> So many thanks for your advice, but this calculation is part of my NCL
>> script, and can not shift to NCO.
>> Best wishes,
>>
>> On Fri, Feb 18, 2022 at 7:03 PM Joseph Zambon <jbzambon at ncsu.edu> wrote:
>>
>>> Setareh,
>>>
>>> NCO utilities might be the easiest way to attack that problem.
>>>
>>> e.g. http://nco.sourceforge.net/nco.html#ncbo
>>> http://nco.sourceforge.net/nco.html#ncap2
>>>
>>> -Joe
>>>
>>>
>>> Joseph B. Zambon, Ph.D.
>>> Research Assistant Professor
>>>
>>> Ocean Observing and Modeling Group
>>> Department of Marine, Earth and Atmospheric Sciences
>>> North Carolina State University
>>> Jordan Hall rm 4140
>>> 919.515.7928
>>> jbzambon at ncsu.edu
>>> www.joezambon.com
>>>
>>> On Feb 18, 2022, at 10:29, Setareh Rahimi via ncl-talk <
>>> ncl-talk at mailman.ucar.edu> wrote:
>>>
>>> Dear NCL users,
>>> I have 4 netcdf files containing temperature ( T(time,lat,lon)). I need
>>> to sum over all these 4 files to have a total temperature value . May I ask
>>> you to kindly advise me how I can  do this please?
>>> many thanks in advance,
>>> Best wishes,
>>>
>>> --
>>> S.Rahimi
>>>
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>>>
>>>
>>
>> --
>> S.Rahimi
>>
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>
>

-- 
S.Rahimi
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