NCL Graphics: REMO-RCM

REMO is a regional climate model created as a joint effort by several German research groups (eg: MPI for Meteorology, DKRZ, DWD, GKSS). A primary focus is concentrated on the hydrological components of the water cycle.

The output format is GRIB. Users should examine the file's contents prior to use via ncl_filedump withe the -itime option:

            ncl_filedump -itime  REMO.grb | less 

In addition to the output one normally sees from ncl_filedump, eg:

         float P_WAT_GDS0_SFC ( initial_time0_hours, g0_lat_1, g0_lon_2 )
            long_name :    Precipitable water
            units :        kg/m^2
            _FillValue :   1e+20
            level_indicator :      1
            gds_grid_type :        0
            parameter_table_version :      128
            parameter_number :     54
            forecast_time :        0
            forecast_time_units :  hours

It is likely that the user will see warning messages like:

         warning:NclGRIB: Unknown grib parameter number detected 
                          (129, center 0, table version 128 grib record 1), 
                          using default variable name (VAR_129)
         warning:NclGRIB: Unknown grib parameter number detected 
                          (130, center 0, table version 128 grib record 30), 
                          using default variable name (VAR_130)
         warning:NclGRIB: Unknown grib parameter number detected 
                          (134, center 0, table version 128 grib record 2), 
                          using default variable name (VAR_134)
         warning:NclGRIB: Unknown grib parameter number detected 
                          (172, center 0, table version 128 grib record 3), 
                          using default variable name (VAR_172)
         warning:NclGRIB: Unrecognized parameter table 
                          (center 0, subcenter 0, table 128), 
                          defaulting to NCEP operational table for standard parameters (1-127): 
                          variable names and units may be incorrect

         [SNIP]

         float VAR_130_GDS0_HYBY ( initial_time0_hours, lv_HYBY3, g0_lat_4, g0_lon_5 )
            long_name :    Unknown Variable Name
            units :        unknown
            _FillValue :   1e+20
            level_indicator :      110
            gds_grid_type :        0
            parameter_table_version :      128
            parameter_number :     130
            forecast_time :        0
            forecast_time_units :  hours

         [SNIP]

The reason for these warning messages is that NCL does not have a valid builtin GRIB table that allows NCL to lookup the variable name and units associated with the GRIB file's parameter id. A sample REMO GRIB table is available: REMO3_WRF_Vtable. However, the information needed to correctly apply the table is not present. As noted by one of the NCL developers:

         It is not going to be possible to support the REMO GRIB table as
         long as they are putting out 0 for the center id. 0 is not a
         recognized center id, so there is no valid way to identify where the 
         GRIB file is coming from.

IMPORTANT NOTE: THE DATA VALUES ARE CORRECTLY UNPACKED. However, the user must manually provide the appropriate information by looking at the REMO GRIB table. See Example 2.