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[GEMPAK #TVE-191694]: problems with decoding grb to grd

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  • Subject: [GEMPAK #TVE-191694]: problems with decoding grb to grd
  • Date: Wed, 26 Jul 2006 10:12:53 -0600
Kathrin,

Your NAGRIB output shows 
>GDS byte        6 (gds.grid_proj) = 50

That means that your data is spherical harmonic coefficients, which is
not a data type that GEMPAK can handle. I looked up the ERA40 information:
http://dss.ucar.edu/datasets/common/ecmwf/ERA40/docs/horizontal-coordinate/index.html#sec1
This mentions that there are 2.5 degree grid data available for some 
parameters. If you have
access to that, you should be able to decode it into GEMPAK format.

Steve Chiswell
Unidata User Support

> Dear GEMPAK support team,
> 
> I'm trying to decode ERA40 data from grb to grd by using NAGRIB. The problem
> is that NAGRIB cannot read the date and time format of my ERA40 dataset.
> GDLIST returns the error [DG -22] when reading the NAGRIB decoded ERA40 file.
> I downloaded the ERA40 dataset from WDCC  (world data center for climate) in
> Germany. They provide ERA40 datasets in grib format. I have also tried to
> decode an ERA40 data file which has been directly provided by ECMWF with the
> same effect. To see the difference in time format I have tried to compare the
> ERA40 dataset with the eta_00hr.grib file, which is an example file provided
> by unidata and which can be decoded without any problems. Unfortunately, the
> programs I'm using to read grib files (cdo) cannot open eta_00hr.grib.
> Could you please help me finding the difference between the ERA40 time format
> in grib and the time format from eta_00hr.grib.
> I have attached the nagrib.fil file which also includes all NAGRIB output
> displayed onto my screen.
> 
> Yours sincerely,
> Kathrin Riemann
> Master student from University of Hamburg, Germany
> 
> 


Ticket Details
===================
Ticket ID: TVE-191694
Department: Support GEMPAK
Priority: Normal
Status: Closed