Re: 20040226:valtime_offset problems gribtonc

Lori,

I received the grib file and created a cdl file for your isabel data.
The cdl from gribtocdl had to be modified a litte because it had
valtime offsets of 0 and 6 because the PRECIP var is actually a time
range and gribtocdl doesn't handle that well. ie

From gribdump:

       Time Range Indicator : Accumulation from P1 to P2
                Time 1 (P1) : 0
                Time 2 (P2) : 6

other vars were similar too:

       Time Range Indicator : Reference Time + P1
                Time 1 (P1) : 6

When gribtonc ran on the data, it only created one record for the 6 hr data.
The cdl is a attached.

Robb...


On Thu, 26 Feb 2004, Robb Kambic wrote:

> On Thu, 26 Feb 2004, Unidata Support wrote:
>
> >
> > ------- Forwarded Message
> >
> > >To: address@hidden
> > >From: Lori Thompson <address@hidden>
> > >Subject: valtime_offset problems
> > >Organization: UCAR/Unidata
> > >Keywords: 200402261855.i1QItjrV024503
> >
> > We recently upgraded to the decoders version 3.0.2. I am converting a
> > dataset from grib to NetCDF. During the conversion, each snapshot file was
> > concatenated using nccatm to produce a time series file. I seem to be
> > running into problems with this newer version where additional points are
> > added to the record dimension during gribtonc, creating additional
> > 9actually doubling) blank frames in the time series. I have made several
> > attempts to manipulate the CDL file so that the record dimension will only
> > have 1 value per file but these efforts failed. Is there a new feature
> > with the upgrade that is causing this, or am I doing something wrong?
>
>
> Lori,
>
> I am not quite sure that what your question is?
>
> The valtime_offsets are extracted from the data files. The
> offsets must be in the raw grib data you used to make the cdl. You could
> use use the gribdump utility to check your grib input file.  ie
>
> % gribdump <rawgrib> | less
> ...
>        Time Range Indicator : Reference Time + Long P1
>                 Time 1 (P1) : 0
>                 Time 2 (P2) : 12
> ...
>
> This would result in a valtime_offset of 12.  You could edit the cdl file
> in the data section.  Removing some of the values for the
> valtime_offset, only used the offsets in the data that you are decoding.
>
> I don't know what the result would be if the variable valtime_offset was
> removed from the data section. You would get some errors but not fatal
> errors.
>
>
> If none of the above ideas work, you might want to use the old version of
> the decoder and modify the gribtocdl file section to look like lines
> 1882-1937 in the latest gribtocdl.  I think that the actual changes might
> be only a couple lines in that section. A simple recompile might solve
> your problem.
>
> Let me know your findings. If you are still having problems, send me your
> cdl an a sample grib file.
>
> Robb....
>
>
> >
> > Thanks,
> > Lori
> >
> > --
> > ----------------------------------------------------
> > Lori A. Thompson
> > Applications Programmer/RS Information Systems, Inc.
> > Geophysical Fluid Dynamics Laboratory/NOAA
> > Princeton University Forrestal Campus/Route 1
> > PO Box 308
> > Princeton, NJ 08542
> > Phone: 609-452-6563
> > Fax:   609-987-5063
> > http://www.gfdl.noaa.gov/~lat
> >
> > --
> > NOTE: All email exchanges with Unidata User Support are recorded in the
> > Unidata inquiry tracking system and then made publically available
> > through the web.  If you do not want to have your interactions made
> > available in this way, you must let us know in each email you send to us.
> >
> > ------- 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/
> ===============================================================================
>

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

netcdf Replace_with_model_name{ 


dimensions:
        record = UNLIMITED ;   // (reference time, forecast time)
        lat = 225 ;            // latitude
        lon = 225 ;            // longitude
        fhg = 1 ;              // fixed height above ground
        bls = 1 ;              // depth below land surface
        level = 21 ;           // isobaric levels
        time_len = 21 ;        // string length for datetime strings
        valtime_offset = 1 ;   // number of offset times
        nmodels = 1 ;          // number of models
        ngrids = 1 ;           // number of grids
        nav = 1 ;              // for navigation
        nav_len = 100 ;        // max string length for navigation 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, time_len) ; // derived from reftime
               datetime:long_name = "reference date and time" ;
               // units YYYY-MM-DD hh:mm:ssZ  (ISO 8601)

        double valtime_offset(valtime_offset) ; // valtime - reftime
               valtime_offset:long_name = "hours from reference time" ;
               valtime_offset:units = "hours" ;

        char   forecasttime(record, time_len) ; // derived from valtime
               forecasttime:long_name = "forecast date and time" ;
               // units YYYY-MM-DD hh:mm:ssZ  (ISO 8601)

        float  fhg(fhg) ;
               fhg:long_name = "fixed height above ground" ;
               fhg:units = "meters" ;

        float  bls(bls) ;
               bls:long_name = "depth below land surface" ;
               bls:units = "cm" ;

        float  level(level) ;
               level:long_name = "isobaric level" ;
               level:units = "hectopascals" ;


        // The following lat and lon coordinate variables are redundant,
        // since the navigation variables provide the necessary information.
        // The extra information is included here for human readability.

        float  lat(lat) ;
               lat:long_name = "latitude" ;
               lat:units = "degrees_north" ;

        float  lon(lon) ;
               lon:long_name = "longitude" ;
               lon:units = "degrees_east" ;

        long   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, ngrids) ;
               grid_number:long_name = "GRIB-1 catalogued grid numbers" ;
               grid_number:_FillValue = -9999 ;

        char   i_dim(nav, nav_len) ;
               i_dim:long_name = "longitude dimension name" ;

        char   j_dim(nav, nav_len) ;
               j_dim:long_name = "latitude dimension name" ;

        int    Ni(nav) ;
               Ni:long_name = "number of points along a latitude circle" ;

        int    Nj(nav) ;
               Nj:long_name = "number of points along a longitude circle" ;

        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" ;

        float  La2(nav) ;
               La2:long_name = "latitude of last grid point" ;
               La2:units = "degrees_north" ;

        float  Lo2(nav) ;
               Lo2:long_name = "longitude of last grid point" ;
               Lo2:units = "degrees_east" ;

        float  Di(nav) ;
               Di:long_name = "longitudinal direction increment" ;
               Di:units = "degrees" ;

        float  Dj(nav) ;
               Dj:long_name = "latitudinal direction increment" ;
               Dj:units = "degrees" ;

        byte   ResCompFlag(nav) ;
               ResCompFlag:long_name = "resolution and component flags" ;

        // end of navigation variables

        float  P_msl(record,lat,lon) ;
               P_msl:long_name = "Pressure reduced to MSL at mean sea level" ;
               P_msl:GRIB_parameter_number = 2 ;
               P_msl:GRIB_level_flag = 102 ;
               P_msl:units = "Pa" ;
               P_msl:_FillValue = -9999.f ;
               P_msl:navigation = "nav" ;

        float  PRECIP(record,lat,lon) ;
               PRECIP:long_name = "Total precipitation at surface of the earth" 
;
               PRECIP:GRIB_parameter_number = 61 ;
               PRECIP:GRIB_level_flag = 1 ;
               PRECIP:units = "kg/m2" ;
               PRECIP:_FillValue = -9999.f ;
               PRECIP:navigation = "nav" ;

        float  u_fhg(record,fhg,lat,lon) ;
               u_fhg:long_name = "u-component of wind at fixed height above 
ground" ;
               u_fhg:GRIB_parameter_number = 33 ;
               u_fhg:GRIB_level_flag = 105 ;
               u_fhg:units = "m/s" ;
               u_fhg:_FillValue = -9999.f ;
               u_fhg:navigation = "nav" ;

        float  u(record,level,lat,lon) ;
               u:long_name = "u-component of wind at isobaric levels" ;
               u:GRIB_parameter_number = 33 ;
               u:GRIB_level_flag = 100 ;
               u:units = "m/s" ;
               u:_FillValue = -9999.f ;
               u:navigation = "nav" ;

        float  v_fhg(record,fhg,lat,lon) ;
               v_fhg:long_name = "v-component of wind at fixed height above 
ground" ;
               v_fhg:GRIB_parameter_number = 34 ;
               v_fhg:GRIB_level_flag = 105 ;
               v_fhg:units = "m/s" ;
               v_fhg:_FillValue = -9999.f ;
               v_fhg:navigation = "nav" ;

        float  v(record,level,lat,lon) ;
               v:long_name = "v-component of wind at isobaric levels" ;
               v:GRIB_parameter_number = 34 ;
               v:GRIB_level_flag = 100 ;
               v:units = "m/s" ;
               v:_FillValue = -9999.f ;
               v:navigation = "nav" ;

        float  T_sfc(record,lat,lon) ;
               T_sfc:long_name = "Temperature at surface of the earth" ;
               T_sfc:GRIB_parameter_number = 11 ;
               T_sfc:GRIB_level_flag = 1 ;
               T_sfc:units = "degK" ;
               T_sfc:_FillValue = -9999.f ;
               T_sfc:navigation = "nav" ;

        float  T_bls(record,bls,lat,lon) ;
               T_bls:long_name = "Temperature at depth below land surface" ;
               T_bls:GRIB_parameter_number = 11 ;
               T_bls:GRIB_level_flag = 111 ;
               T_bls:units = "degK" ;
               T_bls:_FillValue = -9999.f ;
               T_bls:navigation = "nav" ;

        float  T(record,level,lat,lon) ;
               T:long_name = "Temperature at isobaric levels" ;
               T:GRIB_parameter_number = 11 ;
               T:GRIB_level_flag = 100 ;
               T:units = "degK" ;
               T:_FillValue = -9999.f ;
               T:navigation = "nav" ;

        float  RH(record,level,lat,lon) ;
               RH:long_name = "Relative humidity at isobaric levels" ;
               RH:GRIB_parameter_number = 52 ;
               RH:GRIB_level_flag = 100 ;
               RH:units = "percent" ;
               RH:_FillValue = -9999.f ;
               RH:navigation = "nav" ;

        float  Z(record,level,lat,lon) ;
               Z:long_name = "Geopotential height at isobaric levels" ;
               Z:GRIB_parameter_number = 7 ;
               Z:GRIB_level_flag = 100 ;
               Z:units = "gp m" ;
               Z:_FillValue = -9999.f ;
               Z:navigation = "nav" ;


// global attributes
               :history = "2004-03-01 09:43:36 - created by gribtocdl" ; 
               :title = "Enter model definition here" ;
               :Conventions = "NUWG" ;
               :GRIB_reference = "Office Note 388 GRIB" ;
               :GRIB_URL = "http://www.nco.ncep.noaa.gov/pmb/docs/on388/"; ;
               :version = 0.0 ;

data:

 fhg = 35.0 ;
 bls = 50.0 ;
 level = 1000.0, 950.0, 900.0, 850.0, 800.0, 750.0, 700.0, 650.0, 600.0, 550.0, 
      500.0, 450.0, 400.0, 350.0, 300.0, 250.0, 200.0, 150.0, 100.0, 50.0, 
      10.0 ;
 model_id = 70 ;
 valtime_offset = 6 ;


 // Navigation
 nav_model = "GRIB1" ;
 grid_type_code = 0 ;
 grid_type = "Latitude/Longitude" ;
 grid_name = " " ;
 grid_center = 7 ;
 grid_number = 255 ;
 i_dim = "lon" ;
 j_dim = "lat" ;
 Ni = 225 ;
 Nj = 225 ;
 La1 = -14.833000 ;
 Lo1 = -104.833000 ;
 La2 = 59.833000 ;
 Lo2 = -30.167000 ;
 Di = 0.333000 ;
 Dj = 0.333000 ;
 ResCompFlag = 128 ;

 lon =-104.83,-104.50,-104.17,-103.83,-103.50,-103.17,-102.83,-102.50,
      -102.17,-101.84,-101.50,-101.17,-100.84,-100.50,-100.17,-99.84,
      -99.50,-99.17,-98.84,-98.51,-98.17,-97.84,-97.51,-97.17,
      -96.84,-96.51,-96.17,-95.84,-95.51,-95.18,-94.84,-94.51,
      -94.18,-93.84,-93.51,-93.18,-92.84,-92.51,-92.18,-91.85,
      -91.51,-91.18,-90.85,-90.51,-90.18,-89.85,-89.51,-89.18,
      -88.85,-88.52,-88.18,-87.85,-87.52,-87.18,-86.85,-86.52,
      -86.18,-85.85,-85.52,-85.19,-84.85,-84.52,-84.19,-83.85,
      -83.52,-83.19,-82.85,-82.52,-82.19,-81.86,-81.52,-81.19,
      -80.86,-80.52,-80.19,-79.86,-79.52,-79.19,-78.86,-78.53,
      -78.19,-77.86,-77.53,-77.19,-76.86,-76.53,-76.19,-75.86,
      -75.53,-75.20,-74.86,-74.53,-74.20,-73.86,-73.53,-73.20,
      -72.86,-72.53,-72.20,-71.87,-71.53,-71.20,-70.87,-70.53,
      -70.20,-69.87,-69.53,-69.20,-68.87,-68.54,-68.20,-67.87,
      -67.54,-67.20,-66.87,-66.54,-66.20,-65.87,-65.54,-65.21,
      -64.87,-64.54,-64.21,-63.87,-63.54,-63.21,-62.87,-62.54,
      -62.21,-61.88,-61.54,-61.21,-60.88,-60.54,-60.21,-59.88,
      -59.54,-59.21,-58.88,-58.55,-58.21,-57.88,-57.55,-57.21,
      -56.88,-56.55,-56.21,-55.88,-55.55,-55.22,-54.88,-54.55,
      -54.22,-53.88,-53.55,-53.22,-52.88,-52.55,-52.22,-51.89,
      -51.55,-51.22,-50.89,-50.55,-50.22,-49.89,-49.55,-49.22,
      -48.89,-48.56,-48.22,-47.89,-47.56,-47.22,-46.89,-46.56,
      -46.22,-45.89,-45.56,-45.23,-44.89,-44.56,-44.23,-43.89,
      -43.56,-43.23,-42.89,-42.56,-42.23,-41.90,-41.56,-41.23,
      -40.90,-40.56,-40.23,-39.90,-39.56,-39.23,-38.90,-38.57,
      -38.23,-37.90,-37.57,-37.23,-36.90,-36.57,-36.23,-35.90,
      -35.57,-35.24,-34.90,-34.57,-34.24,-33.90,-33.57,-33.24,
      -32.90,-32.57,-32.24,-31.91,-31.57,-31.24,-30.91,-30.57,
      -30.24 ;

 lat =-14.83,-14.50,-14.17,-13.83,-13.50,-13.17,-12.83,-12.50,
      -12.17,-11.84,-11.50,-11.17,-10.84,-10.50,-10.17, -9.84,
       -9.50, -9.17, -8.84, -8.51, -8.17, -7.84, -7.51, -7.17,
       -6.84, -6.51, -6.17, -5.84, -5.51, -5.18, -4.84, -4.51,
       -4.18, -3.84, -3.51, -3.18, -2.84, -2.51, -2.18, -1.85,
       -1.51, -1.18, -0.85, -0.51, -0.18,  0.15,  0.49,  0.82,
        1.15,  1.48,  1.82,  2.15,  2.48,  2.82,  3.15,  3.48,
        3.82,  4.15,  4.48,  4.81,  5.15,  5.48,  5.81,  6.15,
        6.48,  6.81,  7.15,  7.48,  7.81,  8.14,  8.48,  8.81,
        9.14,  9.48,  9.81, 10.14, 10.48, 10.81, 11.14, 11.47,
       11.81, 12.14, 12.47, 12.81, 13.14, 13.47, 13.81, 14.14,
       14.47, 14.80, 15.14, 15.47, 15.80, 16.14, 16.47, 16.80,
       17.14, 17.47, 17.80, 18.13, 18.47, 18.80, 19.13, 19.47,
       19.80, 20.13, 20.47, 20.80, 21.13, 21.46, 21.80, 22.13,
       22.46, 22.80, 23.13, 23.46, 23.80, 24.13, 24.46, 24.79,
       25.13, 25.46, 25.79, 26.13, 26.46, 26.79, 27.13, 27.46,
       27.79, 28.12, 28.46, 28.79, 29.12, 29.46, 29.79, 30.12,
       30.46, 30.79, 31.12, 31.45, 31.79, 32.12, 32.45, 32.79,
       33.12, 33.45, 33.79, 34.12, 34.45, 34.78, 35.12, 35.45,
       35.78, 36.12, 36.45, 36.78, 37.12, 37.45, 37.78, 38.11,
       38.45, 38.78, 39.11, 39.45, 39.78, 40.11, 40.45, 40.78,
       41.11, 41.44, 41.78, 42.11, 42.44, 42.78, 43.11, 43.44,
       43.78, 44.11, 44.44, 44.77, 45.11, 45.44, 45.77, 46.11,
       46.44, 46.77, 47.11, 47.44, 47.77, 48.10, 48.44, 48.77,
       49.10, 49.44, 49.77, 50.10, 50.44, 50.77, 51.10, 51.43,
       51.77, 52.10, 52.43, 52.77, 53.10, 53.43, 53.77, 54.10,
       54.43, 54.76, 55.10, 55.43, 55.76, 56.10, 56.43, 56.76,
       57.10, 57.43, 57.76, 58.09, 58.43, 58.76, 59.09, 59.43,
       59.76 ;

}