Re: 20020430: converting ETA 104 GRIB file to netCDF using gribtonc

On Tue, 30 Apr 2002, Unidata Support wrote:

> 
> ------- Forwarded Message
> 
> >To: address@hidden
> >From: David Ovens <address@hidden>
> >Subject: converting ETA 104 GRIB file to netCDF
> >Organization: University of Washington
> >Keywords: 200204302322.g3UNMna26603 netCDF gribtonc CDL ETA
> 
> Hello,
> 
> I need to convert the ETA 104 GRIB files to netCDF format.  I am a
> novice netCDF person.  I tried using gribdump to put together a *.cdl
> file like I have for some other models, and then tried using gribtonc,
> but I don't get any of the gridded data in the netCDF file -- I just
> get the data I entered in the cdl file.  Do you have any suggestions?
> 
> Thanks for any help.
> 
David,

The way I debug gribtonc is to run it from the command line with verbose
mode, ie

% gribtonc -vl - eta104.cdl eta104.nc < eta104.input

One can also send it to a log file,

% gribtonc -vl log eta104.cdl eta104.nc < eta104.input

Usually the output gives enough information to solve the problem. At this
time, I'm preparing for a workshop as a presenter so I will not have time
to take a detail look at this problem until later next week. Keep me
informed of your status, also I would appreciate a copy of a working cdl
if you solve the problem.

Thanks,
Robb...



> Here is my eta104.cdl file for sea-level pressure and Z at 500 mb:
> 
> =======================================================================
> netcdf eta {          // ETA 40km model in Polar Stereographic Projection
> 
> dimensions:
> 
>       record = UNLIMITED ;    // (reference time, forecast time)
>       level = 1 ;             // isobaric levels for most parameters
> 
>       x = 147 ;
>       y = 110 ;
>       datetime_len = 21 ;     // string length for datetime strings
>       nmodels = 3 ;           // both 80km and 48km models
>       accum = 2 ;             // time range for accumulations
>       nav = 1 ;               // For navigation.  Variables that use
>                               // this dimension define a mapping between
>                               // (x,y) indices and (lat,lon) coords.
> 
>       nav_len = 100 ;         // max length for navigation character strings
> 
> 
> variables:
> 
>       double  reftime(record) ;       // reference time of the model
>               reftime:long_name = "reference time" ;
>               reftime:units = "hours since 1992-1-1" ;
> 
>       double  valtime(record) ;       // forecast time ("valid" time)
>               valtime:long_name = "valid time" ;
>               valtime:units = "hours since 1992-1-1" ;
> 
>       :record = "reftime, valtime" ;  // "dimension attribute" -- means
>                                       // (reftime, valtime) uniquely
>                                       // determine record
> 
>       char    datetime(record, datetime_len) ; // derived from reftime
>               datetime:long_name = "reference date and time" ;
>               // units YYYY-MM-DD hh:mm:ssZ  (ISO 8601)
> 
>       float   valtime_offset(record) ; // derived as valtime-reftime
>               valtime_offset:long_name = "hours from reference time" ;
>               valtime_offset:units = "hours" ;
> 
>       float   level(level) ;
>               level:long_name = "level" ;
>               level:units = "hectopascals" ;
> 
>       int     model_id(nmodels) ;
>               model_id:long_name = "generating process ID number" ;
> 
>       // navigation variables all use nav dimension
> 
>       char    nav_model(nav, nav_len) ;        // navigation parameterization
>               nav_model:long_name = "navigation model name" ;
> 
>       int     grid_type_code(nav) ;
>               grid_type_code:long_name = "GRIB-1 GDS data representation 
> type" ;
> 
>       char    grid_type(nav, nav_len) ;
>               grid_type:long_name = "GRIB-1 grid type" ;
> 
>       char    grid_name(nav, nav_len) ;
>               grid_name:long_name = "grid name" ;
> 
>       int     grid_center(nav) ;
>               grid_center:long_name = "GRIB-1 originating center ID" ;
> 
>       int     grid_number(nav) ;
>               grid_number:long_name = "GRIB-1 catalogued grid numbers" ;
>               grid_number:_FillValue = -9999 ;
> 
>       char    earth_shape(nav, nav_len) ;
>               earth_shape:long_name = "assumed earth shape" ;
> 
>       char    x_dim(nav, nav_len) ;
>               x_dim:long_name = "x dimension name" ;
> 
>       char    y_dim(nav, nav_len) ;
>               y_dim:long_name = "y dimension name" ;
> 
>       int     Nx(nav) ;
>               Nx:long_name = "number of points along x-axis" ;
> 
>       int     Ny(nav) ;
>               Ny:long_name =  "number of points along y-axis" ;
> 
>       float   La1(nav) ;
>               La1:long_name = "latitude of first grid point" ;
>               La1:units = "degrees_north" ;
> 
>       float   Lo1(nav) ;
>               Lo1:long_name = "longitude of first grid point" ;
>               Lo1:units = "degrees_east" ;
> 
>       byte    ResCompFlag(nav) ;
>               ResCompFlag:long_name = "resolution and component flags" ;
> 
>       float   Lov(nav) ;
>               Lov:long_name = "orientation of the grid" ;
>               Lov:units = "degrees_east" ;
> 
>       float   Dx(nav) ;
>               Dx:long_name = "x-direction grid length" ;
>               Dx:units = "meters" ;
> 
>       float   Dy(nav) ;
>               Dy:long_name = "y-direction grid length" ;
>               Dy:units = "meters" ;
> 
>       byte    ProjFlag(nav) ;
>               ProjFlag:long_name = "projection center flag" ;
> 
>       float   Latin1(nav) ;
>               Latin1:long_name = "first intersecting latitude" ;
>               Latin1:units = "degrees_north" ;
> 
>       float   Latin2(nav) ;
>               Latin2:long_name = "second intersecting latitude" ;
>               Latin2:units = "degrees_north" ;
> 
>       float   SpLat(nav) ;
>               SpLat:long_name = "latitude of the southern pole" ;
>               SpLat:units = "degrees_north" ;
> 
>       float   SpLon(nav) ;
>               SpLon:long_name = "longitude of the southern pole" ;
>               SpLon:units = "degrees_east" ;
> 
>       // end of navigation variables
> 
> // global attributes:
>               :history = "created by gribtonc from HDS broadcast" ;
>               :title = "NCEP Global Product Set" ;
>               :Conventions = "NUWG" ;
>               :version = 0.0 ;                // still just a draft
> 
>       float   Psl_et(record, y, x) ;
>               Psl_et:long_name = "mean sea level pressure (ETA model 
> reduction)" ;
>               Psl_et:units = "Pa" ;
>               Psl_et:_FillValue = -9999.f ;
>               Psl_et:navigation = "nav" ;
> 
>       float   Z(record, level, y, x) ;
>               Z:long_name = "geopotential height" ;
>               Z:units = "gp m" ;
>               Z:_FillValue = -9999.f ;
>               Z:navigation = "nav" ;
> 
> data:
> 
>  level = 500;
>  model_id = 83, 84, 89 ;
> 
>  // Navigation
>  nav_model = "GRIB1" ;
>  grid_type_code = 5 ;
>  grid_type  = "Polar Stereographic" ;
>  grid_name = "AWIPS grid #104" ;
>  grid_center = 7 ;
>  grid_number = 104 ;
>  earth_shape = "oblate spheroid (IAU 1965)" ;
>  x_dim = "x" ;
>  y_dim = "y" ;
>  Nx = 147 ;
>  Ny = 110 ;
>  La1 = -0.2680 ;
>  Lo1 = -139.475006 ;
>  ResCompFlag = 8 ;
>  Lov = -105.0 ;
>  Dx = 90755 ;
>  Dy = 90755 ;
>  ProjFlag = 64 ;
> }
> =======================================================================
> 
> 
> -- 
> 
> David Ovens           e-mail: address@hidden
> (206) 685-8108          plan: Real-time MM5 forecasting for Pacific Northwest
> Research Meteorologist
> Dept of Atmospheric Sciences, Box 351640
> University of Washington 
> Seattle, WA  98195
> 
> 
> ------- End of Forwarded Message
> 
> 

===============================================================================
Robb Kambic                                Unidata Program Center
Software Engineer III                      Univ. Corp for Atmospheric Research
address@hidden             WWW: http://www.unidata.ucar.edu/
===============================================================================