[ncl-talk] Wrong time decoding on grib2
David Brown
dbrown at ucar.edu
Tue Aug 4 15:34:31 MDT 2015
Hi Nicolas,
I have confirmed this problem. It appears to happen with the
statistically processed variables, TPRATE, an accumulated quantity and
SNOM, an averaged quantity. I am opening a ticket for this issue. I
can tell you that it will almost definitely involved a change to the
source code to fix it, but hopefully it will be a small change. We
will be able to supply you with a new binary when it gets fixed.
Thanks for bringing this issue to our attention.
-dave
On Tue, Aug 4, 2015 at 3:50 AM, Nicolas GASNIER <ngprod41 at gmail.com> wrote:
> Hello NCL users,
>
> I'm facing another GRIB problem with the new Meteo France datasets.
>
> This is the ARPEGE and AROME model outputs, freely available as GRIB2
> files. Datas are stored in different grib sets for surface data and
> pressure level/height data, with a set for a group of 12 and 6 hours
> forecasts respectively.
>
> NCL can read correctly the first time set (00H12H for ARPEGE for
> example), but it starts to bug for further forecasts. It seems like NCL
> doesn't interpret correctly the time variable, and that problem seems to
> increase as the forecast time increase.
>
> For example, for the first surface dataset for ARPEGE (SP1), if you
> print ncl_filedump, the dimension of forecast_time0 variable
> is 12 for the 00H12H echeances and the dimension of the TPRATE variable
> is (time, lat, lon). It has only 4 for the next 13H24H, and for the
> latest sets (75H84H or 85H96H) it alternates between 1 and 2. The TPRATE
> variable is 2D only (lat, lon). The expected result is 12 forecast hours
> for every set, and the TPRATE variable shoud be always (forecast_time,
> lat, lon), as one can see with a wgrib2 ouput (see example output at end
> of mail).
>
> I can convert to netcdf, using wgrib2 or grib_to_netcdf utility : the
> time dimension becomes correct. But that process crash sometimes - maybe
> due to particularities of the dataset. Anyway, it is too disk and CPU
> intensive to be reasonable for my application.
>
> I hope this issue can be worked around. Any clue about that will be much
> appreciated, even solutions involving source patching and compiling !
>
> The files are too big to be included, but one can get the datasets
> directly on MF web site for a test (use SP1 dataset for example) :
>
> For ARPEGE :
> https://donneespubliques.meteofrance.fr/?fond=produit&id_produit=130&id_rubrique=51
>
> For AROME
> https://donneespubliques.meteofrance.fr/?fond=produit&id_produit=131&id_rubrique=51
>
> Thanks for any help.
>
> Regards
>
> Nicolas Gasnier
>
> -------------------------------------------------
> Result for the 00H12H dataset :
>
> $ ncl_filedump ARPEGE_0.1_00H12H_SP1.grib2
> Copyright (C) 1995-2015 - All Rights Reserved
> University Corporation for Atmospheric Research
> NCAR Command Language Version 6.3.0
> The use of this software is governed by a License Agreement.
> See http://www.ncl.ucar.edu/ for more details.
>
> Variable: f
> Type: file
> filename: ARPEGE_0.1_00H12H_SP1
> path: ARPEGE_0.1_00H12H_SP1.grib2
> file global attributes:
> dimensions:
> forecast_time0 = 13
> lat_0 = 521
> lon_0 = 741
> forecast_time1 = 12
> variables:
>
> ...
>
> float TPRATE_P8_L1_GLL0_acc ( forecast_time1, lat_0, lon_0 )
> center : French Weather Service - Toulouse
> production_status : Operational products
> long_name : Total precipitation rate
> units : kg m-2s-1
> _FillValue : 1e+20
> grid_type : Latitude/longitude
> parameter_discipline_and_category : Meteorological
> products, Moisture
> parameter_template_discipline_category_number : ( 8, 0, 1, 52 )
> level_type : Ground or water surface
> type_of_statistical_processing : Accumulation
> statistical_process_duration : initial time to forecast time
> initial_time : 08/04/2015 (00:00)
>
> integer forecast_time1 ( forecast_time1 )
> long_name : Forecast offset from initial time
> units : hours
> ...
>
> $ wgrib2 ARPEGE_0.1_00H12H_SP1.grib2
> 1:0:d=2015080400:PRES:mean sea level:anl:
> ...
> 144:36148384:d=2015080400:TPRATE:surface:0-1 hour acc fcst:
> 145:36345772:d=2015080400:TPRATE:surface:0-2 hour acc fcst:
> 146:36550429:d=2015080400:TPRATE:surface:0-3 hour acc fcst:
> 147:36778596:d=2015080400:TPRATE:surface:0-4 hour acc fcst:
> 148:36995319:d=2015080400:TPRATE:surface:0-5 hour acc fcst:
> 149:37226250:d=2015080400:TPRATE:surface:0-6 hour acc fcst:
> 150:37469285:d=2015080400:TPRATE:surface:0-7 hour acc fcst:
> 151:37723534:d=2015080400:TPRATE:surface:0-8 hour acc fcst:
> 152:37989302:d=2015080400:TPRATE:surface:0-9 hour acc fcst:
> 153:38266837:d=2015080400:TPRATE:surface:0-10 hour acc fcst:
> 154:38556419:d=2015080400:TPRATE:surface:0-11 hour acc fcst:
> 155:38821541:d=2015080400:TPRATE:surface:0-12 hour acc fcst:
> ...
>
>
> -------------------------------------------------
> Result for the 73H84H dataset :
>
> $ ncl_filedump ARPEGE_0.1_73H84H_SP1.grib2
> Copyright (C) 1995-2015 - All Rights Reserved
> University Corporation for Atmospheric Research
> NCAR Command Language Version 6.3.0
> The use of this software is governed by a License Agreement.
> See http://www.ncl.ucar.edu/ for more details.
>
> Variable: f
> Type: file
> filename: ARPEGE_0.1_73H84H_SP1
> path: ARPEGE_0.1_73H84H_SP1.grib2
> file global attributes:
> dimensions:
> forecast_time0 = 12
> lat_0 = 521
> lon_0 = 741
> variables:
> ...
> float TPRATE_P8_L1_GLL0_acc ( lat_0, lon_0 )
> center : French Weather Service - Toulouse
> production_status : Operational products
> long_name : Total precipitation rate
> units : kg m-2 s-1
> _FillValue : 1e+20
> grid_type : Latitude/longitude
> parameter_discipline_and_category : Meteorological
> products, Moisture
> parameter_template_discipline_category_number : ( 8, 0, 1, 52 )
> level_type : Ground or water surface
> type_of_statistical_processing : Accumulation
> statistical_process_duration : initial time to forecast time
> forecast_time : 72
> forecast_time_units : hours
> initial_time : 08/04/2015 (00:00)
> ...
>
> $ wgrib2 ARPEGE_0.1_73H84H_SP1.grib2
> ...
> 133:34691684:d=2015080400:TPRATE:surface:0-73 hour acc fcst:
> 134:35059823:d=2015080400:TPRATE:surface:0-74 hour acc fcst:
> 135:35429187:d=2015080400:TPRATE:surface:0-75 hour acc fcst:
> 136:35799682:d=2015080400:TPRATE:surface:0-76 hour acc fcst:
> 137:36171501:d=2015080400:TPRATE:surface:0-77 hour acc fcst:
> 138:36544719:d=2015080400:TPRATE:surface:0-78 hour acc fcst:
> 139:36919171:d=2015080400:TPRATE:surface:0-79 hour acc fcst:
> 140:37294798:d=2015080400:TPRATE:surface:0-80 hour acc fcst:
> 141:37671824:d=2015080400:TPRATE:surface:0-81 hour acc fcst:
> 142:38049918:d=2015080400:TPRATE:surface:0-82 hour acc fcst:
> 143:38429238:d=2015080400:TPRATE:surface:0-83 hour acc fcst:
> 144:38809833:d=2015080400:TPRATE:surface:0-84 hour acc fcst:
> ...
>
>
> -------------------------------------------------
> Result for the 85H96H dataset :
>
> $ ncl_filedump ARPEGE_0.1_85H96H_SP1.grib2
> Copyright (C) 1995-2015 - All Rights Reserved
> University Corporation for Atmospheric Research
> NCAR Command Language Version 6.3.0
> The use of this software is governed by a License Agreement.
> See http://www.ncl.ucar.edu/ for more details.
>
> Variable: f
> Type: file
> filename: ARPEGE_0.1_85H96H_SP1
> path: ARPEGE_0.1_85H96H_SP1.grib2
> file global attributes:
> dimensions:
> forecast_time0 = 12
> lat_0 = 521
> lon_0 = 741
> forecast_time1 = 2
> variables:
> ...
> float TPRATE_P8_L1_GLL0_acc ( forecast_time1, lat_0, lon_0 )
> center : French Weather Service - Toulouse
> production_status : Operational products
> long_name : Total precipitation rate
> units : kg m-2 s-1
> _FillValue : 1e+20
> grid_type : Latitude/longitude
> parameter_discipline_and_category : Meteorological
> products, Moisture
> parameter_template_discipline_category_number : ( 8, 0, 1, 52 )
> level_type : Ground or water surface
> type_of_statistical_processing : Accumulation
> statistical_process_duration : initial time to forecast time
> initial_time : 08/04/2015 (00:00)
>
> $ wgrib2 ARPEGE_0.1_85H96H_SP1.grib2
> ...
> 133:33228276:d=2015080400:TPRATE:surface:0-85 hour acc fcst:
> 134:33612201:d=2015080400:TPRATE:surface:0-86 hour acc fcst:
> 135:33997998:d=2015080400:TPRATE:surface:0-87 hour acc fcst:
> 136:34385885:d=2015080400:TPRATE:surface:0-88 hour acc fcst:
> 137:34775283:d=2015080400:TPRATE:surface:0-89 hour acc fcst:
> 138:35165904:d=2015080400:TPRATE:surface:0-90 hour acc fcst:
> 139:35557513:d=2015080400:TPRATE:surface:0-91 hour acc fcst:
> 140:35949966:d=2015080400:TPRATE:surface:0-92 hour acc fcst:
> 141:36343265:d=2015080400:TPRATE:surface:0-93 hour acc fcst:
> 142:36737384:d=2015080400:TPRATE:surface:0-94 hour acc fcst:
> 143:37132325:d=2015080400:TPRATE:surface:0-95 hour acc fcst:
> 144:37528229:d=2015080400:TPRATE:surface:0-4 day acc fcst:
>
>
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