[Met_help] MET/pcp_combine help

[Jeffrey Duda]

John,
I was able to successfully run copygb with your help and now am looking to
run pcp_combine, subtract, to get a one hour precip field from my WRF output
files.  I have isolated the two files (and actually uploaded them to the
server described in previous emails), and used the following command to run
pcp_combine assuming the following:

  "accum1" indicates the accumulation interval to be used from in_file1 in
HH format (required).   -I set this as 12
  "accum2" indicates the accumulation interval to be used from in_file2 in
HH format (required).   -I set this as 11

I got this:

/bin/pcp_combine -subtract WRFPRS_d02.012_00 12 WRFPRS_d02.011_00 11
difference.out
Reading input file: WRFPRS_d02.012_00
Reading input file: WRFPRS_d02.011_00
Performing subtraction command.
Writing output file: difference.out

Figuring that pcp_combine took the difference between two GRIB files, the
output should also be grip, no?  So I tried to convert it to view using
Grads, but got an error when I ran grib2ctl.pl:
"/grib2ctl.pl difference.out > difference_ctl.ctl
found unidentified data
Big problem:
  either difference.out is missing or not a grib file
  or wgrib is not on your path

Please help.  Thank you very much for your help so far.

Jeff Duda

On Fri, Dec 18, 2009 at 3:45 PM, John Halley Gotway <johnhg at rap.ucar.edu>wrote:

> Jeff,
>
> Well I'd first check to see what's actually in that GRIB file using the
> "wgrib" command.  For example, try this:
> wgrib WRFPRS_d02.012_00 | grep APCP
>
> That'll dump out the contents of that GRIB file, looking only for the APCP
> records (accumulated precip).  Look to see if that file really does
> contain a record for 0-12 hour accumulated precip.
>
> If you have more questions about this, it'd probably be easier for you to
> just send me some sample data to take a look at.  If you'd like to do
> that, you could post it to our anonymous ftp site in the following way:
>
> cd "the directory that contains the files you want to send"
> ftp ftp.rap.ucar.edu
> username = anonymous
> password = "your email address"
> cd incoming/irap/met_help
> mkdir duda_data
> cd duda_data
> put WRFPRS_d02.012_00
> put WRFPRS_d02.011_00
> bye
>
> Hope that helps.
>
> John
>
> > John,
> > I am Bill Gallus' student and I am trying to use MODE to verify a WRF
> > model
> > run using accumulated precip.  To do this, I need to match Stage_IV data
> > to
> > my model grid.  To do that, though, I need to get a difference in precip
> > file to compare with Stage_IV data (which has 1 hourly accumulated
> > precip).
> > My WRF files use run total accumulated precip.  I have run WPP on the
> > NetCDF
> > output of the WRF files and now am trying to use pcp_combine -subtract to
> > basically subtract the total accumulated precip from one file from one an
> > hour before it (my NetCDF output interval is 15 minutes).  When I tried
> to
> > run pcp_combine, though, I got an error.  Can you help me with this,
> > please?  Thank you.
> >
> >
> > Here's a screen grab of the command and error:
> >
> > -bash-3.2$ /usr/local/METv2.0/bin/pcp_combine -subtract WRFPRS_d02.012_00
> > 12
> > WRFPRS_d02.011_00 11 20080719_18-17_precipdiff
> > Reading input file: WRFPRS_d02.012_00
> >
> >
> > ERROR: get_field() -> can't find grib code 61 with accumulation of 12
> > hours
> > in grib file: WRFPRS_d02.012_00
> >
> > Jeff Duda
> > --
> > Jeff Duda
> > Iowa State University
> > Meteorology Graduate Student
> > 3134 Agronomy Hall
> > www.meteor.iastate.edu/~jdduda <http://www.meteor.iastate.edu/%7Ejdduda>
> >
>
>
>


-- 
Jeff Duda
Iowa State University
Meteorology Graduate Student
3134 Agronomy Hall
www.meteor.iastate.edu/~jdduda
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.ucar.edu/pipermail/met_help/attachments/20091230/a60a4aa4/attachment.html