Re: NCEP CSFR grb2 errors

Hi Allison, Dennis

Given similar mishaps I had with sequences of NCEP grib1 files,
I would guess the albedo variable may be there, perhaps under a slightly
different name, which I believe is automatically generated by the
NCL libraries, based on the structure and coordinates
of each grib file (which doesn't seem to be constant or stable
over a whole decade or many months).

Have you tried to convert the 17th file in your decade
to netCDF using ncl_convert2nc,
then search the resulting netCDF file header (obtained via ncdump)
for a substring of your variable name (say, 'ALBDO')?
Perhaps compare also with the corresponding results from the
1st or from the 16th file in your decade?

Somehow I always had problems with mangled/modified variable names
in the 5th month, whereas Allison seems to stumble on the 17th.
Does grib hate prime numbers, or does it have a taste for
numerology perhaps? :)
Oh well, why the heck do they use GRIB after all?!

I hope this helps,
Gus Correa

Dennis Shea wrote:
> Hello
>
> v5.1.1 is more than 2 years old. The builtin GRIB2 tables were not
> available at that time. The current NCL version (6.0.0) has no problem
> reading the file(s). You'll have to
>
> %> ncl_filedump flxf03.gdas.197901.grb2 -itime | less
>
> Copyright (C) 1995-2011 - All Rights Reserved
> University Corporation for Atmospheric Research
> NCAR Command Language Version 6.0.0
> 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: flxf03.gdas.197901
> path: flxf03.gdas.197901.grb2
> file global attributes:
> dimensions:
> initial_time0_hours = 1
> lat_0 = 576
> lon_0 = 1152
> lv_DBLL0 = 4
> variables:
> float TMP_P8_L1_GGA0_avg744h ( initial_time0_hours, 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 : 744
> forecast_time_units : hours
>
> [***SNIP***]
> float ALBDO_P8_L1_GGA0 ( initial_time0_hours, lat_0, lon_0 )
> center : US National Weather Service - NCEP (WMC)
> production_status : Operational products
> long_name : Albedo
> units : %
> _FillValue : 1e+20
> grid_type : Gaussian latitude/longitude
> parameter_discipline_and_category : Meteorological
> products, Physical atmospheric properties
> parameter_template_discipline_category_number : ( 8, 0,
> 19, 1 )
> level_type : Ground or water surface
> level : 0
> type_of_statistical_processing : Average of forecast
> averages, each of an equal specified duration, with 6-hour
> intervals between forecasts.
> statistical_process_duration : 3 hours (beginnng at
forecast time)
> number_in_average : 124
> forecast_time : 0
> forecast_time_units : hours
> [***SNIP***]
>
> ================================================
>
> D
>

Allison Steiner wrote:
>
> Hello--
>
> I'm trying to process the NCEP CSFR GRB2 temperature output for
> 1979-2009 and am running into some problems.
>
> The attached script opens the files in a loop and tries to read in a
> specified variable (ALBDO_P8_L1_GGA0) from each file. The script runs
> for the first fifteen months with the usual NCL grib warnings, e.g.:
> warning: Entry (205) not found in code table file
> /usr/share/ncarg/grib2_codetables/ncep/4/4.10.table
>
> However, when it reaches the 16th file,the grib error changes slightly to
>
> warning: NclGRIB2: codetable file
> "/usr/share/ncarg/grib2_codetables/ncep/1/1.3.table" not a valid GRIB2
> code table.
>
> It then crashes on the subsequent file (the 17th) with the following error:
> fatal: NclGRIB2: codetable directory "/usr/share/ncarg/grib2_codetables"
> invalid
> fatal:Could not open (../Ncep/flxf03.gdas.198006.grb2)
> fatal:Either file (f) isn't defined or variable (ALBDO_P8_L1_GGA0) is
> not a variable in the file
> fatal:Execute: Error occurred at or near line 19 in file testncep2.ncl
>
> I would suspect this was something with the libraries, but the script
> runs for multiple months before getting this error. Also, the crash
> always occurs on the 17th file, even if I change the decade of data I'm
> processing, indicating that the error is not due to any one specific
> file. I'm running NCL v. 5.1.1. Two years of monthly data are loaded
> to (ftp.cgd.ucar.edu <http://ftp.cgd.ucar.edu/>) with the beginning file
> extension of flxf03.gdas.YYYYMM.grb2.
>
> Any ideas?
>
> Thank you,
>
> Allison
>
>
> ;************************************
> ; Script to read in NCEP CSFR data 1979-2009
> ;************************************
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
>
> begin
>
> ; list all files
> fili = systemfunc("ls ../Ncep/*.grb2")
> nfil = dimsizes(fili)
>
>
> ; file loop
> do nf=0, nfil-1
> print(nf+" "+fili(nf))
> f = addfile(fili(nf),"r") ; grib
> ntest=f->ALBDO_P8_L1_GGA0
>
> printVarSummary(ntest)
>
> delete(f)
> delete(ntest)
> end do
>
>
> end
>
>
>
>
> ------------------------------------------------------------------------
>
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Received on Wed Jul 20 14:02:29 2011