[Met_help] Problem with GRID-STAT

[John Halley Gotway]

Francesco,

I also wanted to point out something else.

The way the ECMWF data is stored in the file you sent is problematic for MET.  The file you sent contains data for multiple times all concatenated together into a single file.  When you run this
through Grid-Stat, for example, and look for "130/P500", it'll look for GRIB code 130 at pressure level 500.  And it'll use the first record it finds.  Suppose you have 5 records for GRIB code 130 at
pressure level 500 in a single file, all for different times, MET would only be able to access the first one of those 5.

When using MET, you should make sure that your GRIB files contain data only for a single time.

Thanks,
John

Francesco Piani wrote:
> Hi John.
> I upload the files as gzip.
> Thanks for your interest on our problems.
> 
> Have a nice week end.
> Francesco
> 
> --------------------------------------------------
> From: "John Halley Gotway" <johnhg at rap.ucar.edu>
> Sent: Thursday, May 14, 2009 3:28 PM
> To: "Francesco Piani" <piani at lamma.rete.toscana.it>
> Cc: "MET_HELP" <met_help at ucar.edu>
> Subject: Re: [Met_help] Problem with GRID-STAT
> 
>> Francesco,
>>
>> That's an interesting question you raise.  I'm not sure if other users
>> have run ECMWF data through MET.  In reading about ECMWF's use of
>> GRIB, I'm guessing there may be issues with it.
>>
>> But I'd like take a look at the data to see what the options are. 
>> Would you mind sending me the two sample files you reference in your
>> message, as well as the Grid-Stat configuration file you're using?
>>
>> You can post this data to our anonymous ftp site:
>> ftp ftp.rap.ucar.edu
>> username = anonymous
>> password = "your email address"
>> cd incoming/irap/met_help/piani
>> put "your files"
>> bye
>>
>> Please let me know when you've posted the files, and I'll take a look.
>> Unfortunately, I don't know the answer to your question - whether
>> there's an easy way of modifying which parameter table version
>> is used for a GRIB file.  I read through the information on copygb,
>> and it doesn't look like it could do that.  I did look at ECMWF's
>> webpage (http://www.ecmwf.int/products/data/software/) and some of
>> their software tools may be of use, but I'm really not sure.
>>
>> Thanks,
>> John Halley Gotway
>> johnhg at ucar.edu
>>
>> Francesco Piani wrote:
>>> Hi all.
>>> I would like to use MET, in particular GRID-STAT, to compare WRF_NMM
>>> at a resolution of 8km with the ECMWF 0.25° model. I use ggrid to
>>> extract the domain of interest (Italy) and copygb to regrid WRF_NMM
>>> fields over ECMWF grid.
>>>
>>> I noted that the two grib files use different parameter tables (in
>>> particular kpds5).
>>>
>>> ECMWF
>>> 14596:100267650:d=07103112:T:kpds5=130:kpds6=100:kpds7=500:TR=1:P1=0:P2=0:TimeU=1:500
>>> mb:anl:NAve=0
>>> 14597:100274520:d=07103112:Z:kpds5=129:kpds6=100:kpds7=500:TR=1:P1=0:P2=0:TimeU=1:500
>>> mb:anl:NAve=0
>>> 14598:100281390:d=07103112:R:kpds5=157:kpds6=100:kpds7=500:TR=1:P1=0:P2=0:TimeU=1:500
>>> mb:anl:NAve=0
>>> 14599:100288260:d=07103112:U:kpds5=131:kpds6=100:kpds7=500:TR=1:P1=0:P2=0:TimeU=1:500
>>> mb:anl:NAve=0
>>> 14600:100295130:d=07103112:V:kpds5=132:kpds6=100:kpds7=500:TR=1:P1=0:P2=0:TimeU=1:500
>>> mb:anl:NAve=0
>>>
>>> WRF_NMM
>>> 7297:42763434:d=07123100:TMP:kpds5=11:kpds6=100:kpds7=500:TR=0:P1=12:P2=0:TimeU=1:500
>>> mb:12hr fcst:NAve=0
>>> 7296:42756296:d=07123100:HGT:kpds5=7:kpds6=100:kpds7=500:TR=0:P1=12:P2=0:TimeU=1:500
>>> mb:12hr fcst:NAve=0
>>> 7298:42768502:d=07123100:RH:kpds5=52:kpds6=100:kpds7=500:TR=0:P1=12:P2=0:TimeU=1:500
>>> mb:12hr fcst:NAve=0
>>> 7299:42774812:d=07123100:UGRD:kpds5=33:kpds6=100:kpds7=500:TR=0:P1=12:P2=0:TimeU=1:500
>>> mb:12hr fcst:NAve=0
>>> 7300:42780708:d=07123100:VGRD:kpds5=34:kpds6=100:kpds7=500:TR=0:P1=12:P2=0:TimeU=1:500
>>> mb:12hr fcst:NAve=0
>>>
>>> Running GRID-STAT with a file CONFIG with this indication:
>>>
>>> fcst_field[] = [ "11/P850" ];
>>> obs_field[]  = [ "130/P850" ];
>>>
>>> I obtain an error like:
>>>
>>> ***WARNING***: process_scores() -> TMP/P850 not found in GRIB file:
>>> 2007_ecm_cut.grb.
>>>
>>> I imagine the problem was on the parameter table used by ECMWF. Is
>>> there a way to rewrite the GRIB file using the usual table (that
>>> defined by WMO)? I tried to use copygb with the option "-k" but with
>>> any results.
>>> Any suggestions?
>>>
>>> Francesco Piani
>>>
>>> Dott. Ing. Francesco Piani
>>> Weather Forecaster
>>> LaMMA Consortium - Hydrological Service Tuscany Region
>>> Via Madonna del Piano 10
>>> Sesto Fiorentino (FI)
>>> piani at lamma.rete.toscana.it
>>> francesco.piani at regione.toscana.it
>>>
>>>
>>> ------------------------------------------------------------------------
>>>
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