Problems when i convert Grib2 to Netcdf4

Question

I got some problems when i try to convert some grib files form CFSR. when i use ncl_convert2ncin the unix shell, the nc file information is like this :

 netcdf flxf01.gdas.197901 {
dimensions:
        ygrid_0 = UNLIMITED ; // (0 currently)
        lv_DBLL0 = 4 ;

variables:

// global attributes:
                :creation_date = "Sun Nov 12 11:29:36 AEDT 2017" ;
                :NCL_Version = "6.3.0" ;
                :system = "Linux charcoalp-Lenovo-Erazer-Y50-70 4.10.0-38-generic #42-Ubuntu SMP Tue Oct 10 13:24:27 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux" ;
                :Conventions = "None" ;
                :grib_source = "flxf01.gdas.197901.grb2" ;
                :title = "NCL: convert-GRIB-to-netCDF" ;
}

and this only happen when i convert CFSR data grib2 files.

here is part of information of the origin file:

Nio file:   flxf01.gdas.197901.grb2
   global attributes:
   dimensions:
      lat_0 = 576
      lon_0 = 1152
      lv_DBLL0 = 4
   variables:
      float TMP_P8_L1_GGA0_avg744h [ lat_0, lon_0 ]
         center :   US National Weather Service - NCEP (WMC)
         production_status :    Operational products
         long_name :    Temperature
         units :    K
         _FillValue :   1e+20
         grid_type :    Gaussian latitude/longitude
         parameter_discipline_and_category :    Meteorological products, Temperature
         parameter_template_discipline_category_number :    [8, 0, 0, 0]
         level_type :   Ground or water surface
         level :    0
         type_of_statistical_processing :   Average
         statistical_process_duration : 744 hours (ending at forecast time)
         forecast_time :    745
         forecast_time_units :  hours
         initial_time : 01/01/1979 (00:00)
      float TMP_P8_L103_GGA0_avg744h [ lat_0, lon_0 ]
         center :   US National Weather Service - NCEP (WMC)
         production_status :    Operational products
         long_name :    Temperature
         units :    K
         _FillValue :   1e+20
         grid_type :    Gaussian latitude/longitude
         parameter_discipline_and_category :    Meteorological products, Temperature
         parameter_template_discipline_category_number :    [8, 0, 0, 0]
         level_type :   Specified height level above ground (m)
         level :    2
         type_of_statistical_processing :   Average
         statistical_process_duration : 744 hours (ending at forecast time)
         forecast_time :    745
         forecast_time_units :  hours
         initial_time : 01/01/1979 (00:00)

as you can see it is able to find the variables from the grib file. So why the nc file is empty? ncl_convert2nc do work for Grib files of JRA-55 reanalysis dataset. Can anyone help me find where is the problem?

Answer 1

Just out of interest, have you tried using CDO? I think the command is:

cdo -f nc4 copy in.grb out.nc