ARPEGE: Complex packing?

Wesley Ebisuzaki Wesley.Ebisuzaki at NOAA.GOV
Fri Aug 11 10:11:20 EDT 2006


Christian,

    The problem is not with using a thinned gaussian/lat-lon grid as
suggested by another reply
(the current grib2ctl handles those grids).  The problem is that the
grib file is using "complex" packing
of gridded data.  Many codes (wgrib, GrADS, NCEP fortran library, and
probably many others) don't
handle this type of data because nobody used this packing method and
sample data was not readily available.
I would suspect that the GrADS developers are more worried about adding
grib-2 support than adding
complex-packing to their grib-1 code.

       Wesley Ebisuzaki






Christian Grob wrote:
> Dear wise GrADS User,
> for several days I'm desperately trying to process .grb files from the french weather forecasting system Arpege. With wgrib I read the header of the dataset; using grib2ctl.pl I created a descriptor file. The xdef/ydef/zdef did not match, so I changed them according to the values I decoded with wgrib.
> Using gribmap for creating a .idx file shows me: "grib record contains harmonic or complex packing". Trying to open the file in GrADS yields to "entire grid undefined".
> What does that mean? is there a mistake in the ctl file? how can I open the arpege grb-file in Grads?
>
> Thanks for all replies
>
> Christian
>
> **********************************************
> The .ctl file:
>
> dset ^111.grb
> index ^111.grb.idx
> undef 9.999E+20
> title 111.grb
> dtype grib 255
> options yrev
> ydef 111 linear 35.000000 0.2
> xdef 141 linear -11.000000 0.200000
> tdef 1 linear 12Z02aug2006 1mo
> zdef 1 levels 1000
> vars 1
> RHprs  0 52,100,1000  ** Relative humidity [%]
> ENDVARS
>
> **********************************************
> write a mail for getting the tedious .grb file
> **********************************************
>
> --
>
>
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