[ncl-talk] A question about GRIB to netCDF

Dennis Shea shea at ucar.edu
Wed Apr 29 20:52:05 MDT 2015 

Those are warning messages. NCL uses a lookup table to find the 'long_name'
and 'units' of the 'parameter_number'. The messages are saying there were
no entries in the lookup table for the parameter_number.

You should realize that GRIB is a bit of a 'moving target'. The operational
centers can add new parameters over time. It is a nuisance to keep up with
these but the NCL GRIB expert does his best to add new parameters in every
release.

     float VAR_24_GDS0_SFC ( g0_lat_0, g0_lon_1 )
         center :       European Center for Medium-Range Weather Forecasts
(RSMC)
         long_name :    Unknown Variable Name
         units :        unknown
         _FillValue :   1e+20
         level_indicator :      1
         gds_grid_type :        0
         parameter_table_version :      228
         parameter_number :     24              <================
         forecast_time :        3
         forecast_time_units :  hours
         initial_time : 04/22/2015 (00:00)

NOTE: the values are decoded correctly.

---
NCL 6.3.0 has added the entries.

     float DEG0L_GDS0_SFC ( g0_lat_0, g0_lon_1 )
         center :       European Center for Medium-Range Weather Forecasts
(RSMC)
         long_name :    Zero degree level
         units :        m
         _FillValue :   1e+20
         level_indicator :      1
         gds_grid_type :        0
         parameter_table_version :      228
         parameter_number :     24               <============
         forecast_time :        3
         forecast_time_units :  hours
         initial_time : 04/22/2015 (00:00)

      float 100U_GDS0_SFC ( g0_lat_0, g0_lon_1 )
         center :       European Center for Medium-Range Weather Forecasts
(RSMC)
         long_name :    100 metre U wind component
         units :        m s**-1
         _FillValue :   1e+20
         level_indicator :      1
         gds_grid_type :        0
         parameter_table_version :      228
         parameter_number :     246   <===============
         forecast_time :        3
         forecast_time_units :  hours
         initial_time : 04/22/2015 (00:00)


      float 100V_GDS0_SFC ( g0_lat_0, g0_lon_1 )
         center :       European Center for Medium-Range Weather Forecasts
(RSMC)
         long_name :    100 metre V wind component
         units :        m s**-1
         _FillValue :   1e+20
         level_indicator :      1
         gds_grid_type :        0
         parameter_table_version :      228
         parameter_number :     247          <==================
         forecast_time :        3
         forecast_time_units :  hours
         initial_time : 04/22/2015 (00:00)

====================

The unusual thing is that NCL v6.2.0, 6.2.1 and  6.3.0 fail to import the
desired variable. NCL 'seg faults' ... this should not happen. This simple
script fails:

begin

  vinName = "TP_GDS0_SFC"    ; total precipitation
  finName = "ECMWF.I2015042200.003.F2015042203.grib1"
  fin     = addfile(finName,"r")
  print(fin)                                      ; like ncl_filedump

  x = fin->$vinName$
  x = x(::-1,:)
  printVarSummary(x)


  voutName = "rain"
  foutName = voutName+".ECMWF.nc"

  system("rm -f "+foutName)
  ncdf_out=addfile(foutName,"c")
  ncdf_out->$voutName$ = x

end

=================

A JIRA ticket has been opened: NCL-2213
<https://vets.development.ucar.edu/jira/browse/NCL-2213>

==================
Sorry ... we will keep you informed


On Wed, Apr 29, 2015 at 8:40 PM, Kyle Griffin <ksgriffin2 at wisc.edu> wrote:

> Your version of NCL is quite old. NCL 6.3.0 is the current version, and
> that includes many updates to the GRIB tables that would possibly take care
> of the errors you see. It appears you are trying to read a relatively
> recent ECMWF file, which likely has some variables that were added to the
> model output at some point in the last two years. The good news is that,
> unless you are trying to use those more recently defined variables, your
> file has likely converted successfully.
>
> Please update your NCL version, if you are able, and let the list know if
> you still have problems after that.
>
> Kyle
> On Apr 29, 2015 7:52 PM, "Crystal" <jinjing_qiu at 163.com> wrote:
>
>> Dear Professor:
>> I am writing to you as I have a quetion about GRIB to netCDF. The bug
>> report is described below.
>> 1、The version of NCL：NCL V6.1.2
>> 2、Please find the scripts and data  in the attachment.
>> 3、The error message:
>> Copyright (C) 1995-2013 - All Rights Reserved
>>  University Corporation for Atmospheric Research
>>  NCAR Command Language Version 6.1.2
>>  The use of this software is governed by a License Agreement.
>>  See http://www.ncl.ucar.edu/ for more details.
>> warning:NclGRIB: Unknown grib parameter number detected (24, center 98,
>> table version 228 grib record 60), using default variable name (VAR_24)
>> warning:NclGRIB: Unknown grib parameter number detected (246, center 98,
>> table version 228 grib record 72), using default variable name (VAR_246)
>> warning:NclGRIB: Unknown grib parameter number detected (247, center 98,
>> table version 228 grib record 121), using default variable name (VAR_247)
>> Segmentation fault (core dumped)
>> Linux TC5000 2.6.32-220.el6.x86_64 #1 SMP Wed Nov 9 08:03:13 EST 2011
>> x86_64 x86_64 x86_64 GNU/Linux
>> 4、The type of system:gcc (GCC) 4.4.6 20110731 (Red Hat 4.4.6-3)
>> Copyright (C) 2010 Free Software Foundation, Inc.
>> This is free software; see the source for copying conditions.  There is NO
>> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
>> PURPOSE.
>>
>> Look forward to your feedbacks soon.Your help is highly appreciated.
>>
>> Kind Regards,
>> Crystal
>> *从网易163邮箱发来的云附件*
>>
>> <http://fs.163.com/fs/display/?p=X-NETEASE-HUGE-ATTACHMENT&file=saBV1PK54hIt0tXQL69IBEev1npeMcu1kjMd2TKNgLZDazAecAdcnpmeCm5l4gGBKb5ojTO-lTYW44t9FEJLQg&title=A%20question%20about%20GRIB%20to%20netCDF>
>> ECMWF.I2015042200.003.F2015042203.grib1
>> <http://fs.163.com/fs/display/?p=X-NETEASE-HUGE-ATTACHMENT&file=saBV1PK54hIt0tXQL69IBEev1npeMcu1kjMd2TKNgLZDazAecAdcnpmeCm5l4gGBKb5ojTO-lTYW44t9FEJLQg&title=A%20question%20about%20GRIB%20to%20netCDF>
>> (60.4M, 2015年5月13日 16:42 到期)
>> 下载
>> <http://fs.163.com/fs/display/?p=X-NETEASE-HUGE-ATTACHMENT&file=saBV1PK54hIt0tXQL69IBEev1npeMcu1kjMd2TKNgLZDazAecAdcnpmeCm5l4gGBKb5ojTO-lTYW44t9FEJLQg&title=A%20question%20about%20GRIB%20to%20netCDF>
>>
>> <http://fs.163.com/fs/display/?p=X-NETEASE-HUGE-ATTACHMENT&file=saBV1PK54hIt0tXQL69IBEev1npeMcu1kjMd2TKNgLYjNfiAjqGkIArkRAGm5H52WeM5sP-5RcTTpUe-SCxeMg&title=A%20question%20about%20GRIB%20to%20netCDF>
>> GET_ECMWF_APCP.ncl
>> <http://fs.163.com/fs/display/?p=X-NETEASE-HUGE-ATTACHMENT&file=saBV1PK54hIt0tXQL69IBEev1npeMcu1kjMd2TKNgLYjNfiAjqGkIArkRAGm5H52WeM5sP-5RcTTpUe-SCxeMg&title=A%20question%20about%20GRIB%20to%20netCDF>
>> (866B, 2015年5月13日 16:44 到期)
>> 下载
>> <http://fs.163.com/fs/display/?p=X-NETEASE-HUGE-ATTACHMENT&file=saBV1PK54hIt0tXQL69IBEev1npeMcu1kjMd2TKNgLYjNfiAjqGkIArkRAGm5H52WeM5sP-5RcTTpUe-SCxeMg&title=A%20question%20about%20GRIB%20to%20netCDF>
>>
>>
>>
>>
>>
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