[Met_help] Problems with copygb

Justin Arnott Justin.Arnott at noaa.gov
Thu Oct 4 13:42:04 MDT 2007

Good Afternoon,

I am using the copygb utility to regrid some WRF precip (variable: 
apcpsfc) output onto a common grid with another dataset (NCEP Stage 4 
precip) to prepare it for use in the MODE verification software.  I 
noticed that for certain time periods (e.g. forecast hour 1) the grib 
output using bilinear interpolation to the new grid gives me a constant 
"0" field, even though the apcpsfc field in the original grib file is 
nonzero.  My command line input follows:

copygb -g"255 0 86 43 40000 276000 128 45880 287900 140 140" -x 
2007020700_BGM-ARW.F00100.grb out.grb

The grb file is a 1 hour output file from WRF.  Interestingly, other 
fields, such as tmpprs or prmslmsl seem to go work fine.
Thinking that the interpolation type might have caused the problem, I 
asked for no interpolation using:

copygb -x 2007020700_BGM-ARW.F00100.grb out.grb

This still gives me a resultant precip field that is filled with zeroes.

Does anyone see anything wrong with my input or how I'm using copygb?  I 
appreciate your help in advance.

I also sent this email along to the WRF email list as copygb is part of 
the WRF  Post-Processor.

Justin Arnott
NWS Binghamton

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