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

[Dennis Shea]

"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
>>
>> _______________________________________________
>> ncl-talk mailing list
>> ncl-talk at mailman.ucar.edu
>> List instructions, subscriber options, unsubscribe:
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>>
>>
>>
>
> --
> S.Rahimi
>
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