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UPP fails to convert files

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Dear All,

I am trying to the UPP utility to convert WRF output files to a GRIB format. I have compiled UPP correctly and I am trying to convert WRF output to either Grib1 or Grib2.

However this is failing with a segmentation fault. I have attached the last 100kBytes of the file unipost_d03 that is generated during the conversion one for Grib2 and for Grib1.

For GRIB2 the process fails, for GRIB1 a unipost file is created but the output file that is created is very small in relationship to the original data (e.g. 1.7kB)

Any help would be appreciated,



  • Grib2_Error.txt
    97.7 KB · Views: 53
  • Grib1_Error.txt
    9.8 KB · Views: 48
Can you send the full unipost.out file for at least the grib2. It seems there might be an issue reading in the data, it doesn't look like it is reading in your pressure field and time correctly, but that info would be toward the beginning of the log. I realize the log file gets quite large with the checks for monotonic pressure, so if it is too big, at least send the beginning of the *.out

Thanks for your reply,

I am attaching the log of the first 10,000 lines. The .out file is around 1.2Gb large. At some point the .out file has the error "NetCDF error: NetCDF: Variable not found, NetCDF error in wrf_io.F90, line 3345"

You mentioned that the pressure and time have not been read correctly, does it point to an error in the WRF output? The WRF installation is standard without any changes.



  • log.txt
    657.8 KB · Views: 53
Thank you for sending that - I just wanted to check some things. I don't see issues with the time. Just to be sure, in your run script do you have startdate=2020111400 and then your fcst hours based off that initial date?
I don't see errors about this, but your wrfout has the variable P_HYD and it looks okay?

More likely the culprit:
It looks like you're running with a single processor - have you tried increasing the number of processors? You do have quite a large domain. Trying to run with too few/many processors can give some strange and misleading errors!

Just a note on these errors (NetCDF error: NetCDF: Variable not found, NetCDF error in wrf_io.F90, line 3345)
UPP tries to read in a number of variables for your model file and many of them may not be present in your model output. This is fine as long as it's not a variable UPP requires (tmp/pres/u/v/etc) in order to run correctly.