Re: Re: [ncl-talk] tips to unstagger data from WRF

From: Erik Noble <enoble_at_nyahnyahspammersnyahnyah>
Date: Tue, 11 Dec 2007 11:18:57 -0500

Hi.
The post processor does not install on the APPLE or the SGI machine we
are using.
Unfortunately, the post processor step is not an option for me.

Gary or anyone else, do you still have advice about destaggerring
after converting to pressure levels.
the converting to pressure command can be found here:
http://www.mmm.ucar.edu/wrf/users/graphics/NCL/Examples/PressureLevel1/wrf_PressureLevel1.ncl

Where an example of the interpret to pressure command is: IT HAS TO
BE PERFORMED IN A DO LOOP FOR TIME (bummer!!!)

variable = wrf_user_getvar(a,"variable",it) ; variable of interest
p = wrf_user_getvar(a, "pressure",it) ; pressure is our vertical coordinate

do it = 0,ntimes-1 ; TIME LOOP
    do level = 0,nlevels-1 ; LOOP OVER LEVELS
      pressure = 700 ; Sample Pressure level
      Variable_Plane = wrf_user_intrp3d(variable,p,"h",pressure,0.,False)
     end do ; END OF LEVEL LOOP
  end do ; END OF TIME LOOP

After this what is the step for unstaggering? The WRF-Help team does
not provide anymore assistance beyond this step.
-Erik

On Dec 11, 2007 8:08 AM, Jan Ploski <Jan.Ploski_at_offis.de> wrote:
> Gerry Creager <gerry.creager_at_tamu.edu> schrieb am 12/11/2007 02:03:49 PM:
>
>
> > Jan Ploski wrote:
> > > ncl-talk-bounces_at_ucar.edu schrieb am 12/11/2007 12:46:43 AM:
> > >
> > >> I am trying to look at 700 mb winds. Correct me if I am wrong but to
> do
> > > this
> > >> brings in an extra step of interpolating to pressure level using
> WRF-NCL
> > >> code.
> > >> So first I have to interpolate the data usingthe wrf_interp-3d
> function
> > > and
> > >> then use the " wrf_uvmet" function?
> > >
> > > Hello,
> > >
> > > This task is certainly doable with NCL alone. However, we solved it
> (for
> > > computing wind velocity at a given relative height above the terrain
> > > surface) in two steps:
> > >
> > > 1. Run NCEP WRF Postprocessor on the WRF output to destagger and
> extract
> > > U, V WIND ON MDL SFCS, HEIGHT ON MDL SFCS, SURFACE HEIGHT.
> > > 2. Read in the resulting GRIB file with NCL and interpolate to a
> desired
> > > height using wrf_interp_3d_z.
> > >
> > > I think you could do much the same for "ON PRESS SFCS".
> >
> > Does this work for ARW as well as NMM? I was under the impression the
> > Postprocessor was only for NMM code.
>
> The NMM postprocessor and the described method both work for ARW (this is
> what we are using).
>
> The documentation is at
> http://www.dtcenter.org/wrf-nmm/users/docs/user_guide/WPS/users_guide_nmm_chap7_v1_WPS.htm
>
> Best regards,
> Jan Ploski
>
> --
> Dipl.-Inform. (FH) Jan Ploski
> OFFIS
> Betriebliches Informationsmanagement
> Escherweg 2 - 26121 Oldenburg - Germany
> Fon: +49 441 9722 - 184 Fax: +49 441 9722 - 202
> E-Mail: Jan.Ploski@offis.de - URL: http://www.offis.de
>
>
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Received on Tue Dec 11 2007 - 09:18:57 MST

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