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problem converting GrADs ctl to netcdf JRA-55, Open Error: Unknown keyword in description file

Added by Martin Jury over 9 years ago

Dear cdo team,

I am having problems converting a GrADs ctl file to netcdf and was hoping you can help me. Input data are multiple grb files from the Japanese Reanalysis JRA-55.
Any help would be highly appreciated.

Cheers Martin

I have copied the command, ctl-file and the error message below:

cdo -f nc import_binary anl_surf125.monthly.ctl tas.nc

Open Error: Unknown keyword in description file
--> The invalid description file record is:
--> index ^anl_surf125.monthly.idx
The data file was not opened.
cdo import_binary (Abort): Open failed!

less anl_surf125.monthly.ctl

dset ^anl_surf125.%y4%m2
index ^anl_surf125.monthly.idx
undef 9.999E+20
title anl_surf125 * produced by grib2ctl v0.9.12.5p41
dtype grib 255
options yrev template
ydef 145 linear -90.000000 1.25
xdef 288 linear 0.000000 1.250000
tdef 684 linear 00Z01Jan1958 1mo
zdef 1 linear 1 1
vars 9
DEPR2m 0 18,105,2 * 2 m above ground Dew-point depression [K]
POTsfc 0 13,1,0 *
surface Potential temperature [K]
PRESsfc 0 1,1,0 * surface Pressure [Pa]
PRMSLmsl 0 2,102,0 *
mean-sea level Pressure reduced to MSL [Pa]
RH2m 0 52,105,2 * 2 m above ground Relative humidity [%]
SPFH2m 0 51,105,2 *
2 m above ground Specific humidity [kg/kg]
TMP2m 0 11,105,2 * 2 m above ground Temperature [K]
UGRD10m 0 33,105,10 *
10 m above ground u-component of wind [m/s]
VGRD10m 0 34,105,10 ** 10 m above ground v-component of wind [m/s]
ENDVARS


Replies (3)

RE: problem converting GrADs ctl to netcdf JRA-55, Open Error: Unknown keyword in description file - Added by Guillermo Duran almost 6 years ago

Hi Martin,
I'm curious if you were able to solve this issue.
I'm having the exact same error using a different dataset. I'm able to open the files in GRADS but when I try to convert them to netcdf using cdo:

cdo -f nc import_binary r_pgb.ctl test_a1980.nc

I get this:

Open Error: Unknown keyword in description file
--> The invalid description file record is:
--> index ^r_pgb.idx
The data file was not opened.

Any clue of what can be the problem?

RE: problem converting GrADs ctl to netcdf JRA-55, Open Error: Unknown keyword in description file - Added by Uwe Schulzweida almost 6 years ago

CDO supports only the following components of a GrADS control file:

    BYTESWAPPED, CHSUB, DSET, ENDVARS, FILEHEADER, HEADERBYTES, OPTIONS, TDEF, TITLE, 
    TRAILERBYTES, UNDEF, VARS, XDEF, XYHEADER, YDEF, ZDEF
The INDEX component is not supported! As far as I know the INDEX component is needed for GRIB files. The GRIB format is also not supported by this operator! import_binary was implemented only for binary data.
Here is an example to convert GRIB data to NetCDF with CDO:
cdo -f nc copy file.grb file.nc

RE: problem converting GrADs ctl to netcdf JRA-55, Open Error: Unknown keyword in description file - Added by Layla Smith almost 2 years ago

Uwe Schulzweida, I have been having the same issues as the other users when downloading JRA-55 data. I understand that import_binary does not support GRIB format, but do you know if there is an operator that does support it? I cannot simply convert the GRIB file to a NetCDF using that cdo command because the GRIB file is stored inside a DAT file.

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