[Wrf-users] time averaging of variables

[Hein Zelle]

Manda Adams wrote:

>   I am going to be doing some rather long simulations (~90days) to get at
> some seasonal averages.  In order to conserve disk space during these
> massive runs, I am hoping to write a script to extract the basic fields
> (wind, temp, mixing ratio, etc) from the netcdf as the files are being
> written, and create a time averaged dataset.  Since we are mostly
> interested in the time averages of the variables, it would save us a lot
> of disk space to keep only the time averaged fields and delete the
> instantaneous fields.  Has any one else ever tried this?  And if so, do
> you have any scripts you would be willing to share?

I don't have ready-made scripts for saving time averaged variables,
but you may want to take a look at either ferret or the netcdf
operators (nco).  Especially the latter (command-line operators) are
very quick and useful for this kind of work.  If you revert to an
analysis tool like ferret, either matlab or grads will probably also
do the trick.

NCO example:

extract a limited number of variables from a wrf output file, leave
the rest unchanged:

ncks -v u10,v10,t2   wrfout_d01_2008??????   stripped_output_file.nc

average over time:

ncwa -a time  stripped_output_file.nc  time_averaged_output_file.nc


You can easily script these things from bash or perl, handy if you
have a lot of shorter netcdf files.

Kind regards,

     Hein Zelle


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  dr. ir. Hein Zelle

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