Re: grib to netcdf conversion

From: Mary Haley <haley_at_nyahnyahspammersnyahnyah>
Date: Wed, 29 Mar 2006 13:54:38 -0700 (MST)

Hi all,

The solution to this was to upgrade to the latest version (a033) of
NCL.

Every release of NCL usually contains some kind of GRIB update, so it's
always a good idea to check your version of NCL if it's not handling your
GRIB files properly.

--Mary

On Wed, 15 Mar 2006, Kirby, Stephen (Civ, ARL/CISD) wrote:

> Hello Dennis et. al.,
>
> About 6 months back, you wrote a NCL script for me (which I greatly
> appreciate!!) to convert GRIB data (RUC weather model output) to netCDF.
> I'm using the resultant netCDF file as input to the "LAPS" data
> assimilation model. I thought all was ok till taking a closer look at
> the logs.
>
> They indicated that LAPS was not finding height and temperature data
> among others. I then compared the sample RUC netCDF file from the LAPS
> home page against the RUC netCDF created from your script Dennis, and
> saw that the parameter names differ, some of the attributes differ, and
> I'm not getting all of the parameters seen in the sample netCDF from the
> LAPS site.
>
> ==============(1) For ex., the parameters it can't translate:
> ======================================================
>
> warning:NclGRIB: Unknown grib parameter number detected (170), using
> default variable name (VAR_170)
> warning:NclGRIB: Unknown grib parameter number detected (178), using
> default variable name (VAR_178)
> warning:NclGRIB: Unknown grib parameter number detected (171), using
> default variable name (VAR_171)
> warning:NclGRIB: Unknown grib parameter number detected (179), using
> default variable name (VAR_179)
> warning:NclGRIB: Unknown grib parameter number detected (198), using
> default variable name (VAR_198)
> warning:NclGRIB: Unknown grib parameter number detected (186), using
> default variable name (VAR_186)
> warning:NclGRIB: Unknown grib parameter number detected (187), using
> default variable name (VAR_187)
> warning:NclGRIB: Unknown grib parameter number detected (188), using
> default variable name (VAR_188)
>
> Is there a way to extract these from the GRIB? Is an updated GRIB (or
> NCL) table needed?
>
> ===========(2) How can I go about renaming a parameter and altering
> (some of the) attributes, for ex., need to go======================
>
> from:
>
> float HGT_236_HYBL(z, x, y) ;
>
> HGT_236_HYBL:center = "US Weather Service - National
> Met. Center" ;
>
> HGT_236_HYBL:long_name = "Geopotential height" ;
>
> HGT_236_HYBL:units = "gpm" ;
>
> HGT_236_HYBL:_FillValue = -999.f ;
>
> HGT_236_HYBL:level_indicator = 109 ;
>
> HGT_236_HYBL:grid_number = 236 ;
>
> HGT_236_HYBL:parameter_number = 7 ;
>
> HGT_236_HYBL:forecast_time = 0 ;
>
> HGT_236_HYBL:initial_time = "03/08/2006 (00:00)" ;
>
>
>
> to:
>
> float hgt(record, z, y, x) ;
>
> hgt:long_name = "geopotential height" ;
>
> hgt:units = "gp m" ;
>
> hgt:z = "z_dim" ;
>
> hgt:record = "reftime, valtime" ;
>
> hgt:valid_range = -1000.f, 50000.f ;
>
> hgt:_FillValue = -9999.f ;
>
> hgt:navigation_var = "nav" ;
>
> hgt:nimbus_name = "GH" ;
>
> hgt:nimbus_level = "Hybrid" ;
>
>
>
> although I don't see a reftime or valtime parameter in my translated
> netCDF so don't know how to insert a "record" dimension.
>
>
>
> For reference Dennis, I'll attach the NCL script you created for me.
>
>
>
> TIA,
>
>
>
> Steve
>
>
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Received on Wed Mar 29 2006 - 13:54:38 MST

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