[gradsusr] R: About forecast validity and geographical zone.

[Davide Sacchetti]

On Mon, 2010-04-12 at 15:18 +0200, Diego Morelli wrote:
> Ok Davide.
> Can you say me if I have understood:
>  1- The "grib2ctl.pl -verf <filename>" give me information (on tdef) about
> the expiration time of forecast, while "grib2ctl.pl <filename>" give me
> information about the start time of forecast.
> 

the "grib2ctl.pl -verf <filename>" command prints out how your .ctl file
should be written: grib2ctl.pl -verf test.grb > test.ctl
Your .ctl file can control all the TDEF defined by the command above.
if you do not use -verf option you loose forecast verification times
(useful only if your grib contains just analysis)



> 2- If I want to plot on GrADS all the meteo maps contained in a unique grib
> file, I have to split this file in more files each one having information on
> a unique geographical zone and a unique validity, so that I can use GrADS
> for each file: GrADS works on a sequence of grib records that are referred
> all to a unique geographical zone and a unique validity.
> 

You have to split when you have different areas or different
resolutions.
If your grib file contains more than one analysis and some forecasts it
is easier to split the grib according to the different analysis (e.g.: 1
file should contain only one area, one resolution and one analysis with
many forecasts). Another chance is to use gribmap options.


Bye bye
Davide

> Thank you in advance,
> 
> Diego
> 
> 
> -----Messaggio originale-----
> Da: gradsusr-bounces at gradsusr.org [mailto:gradsusr-bounces at gradsusr.org] Per
> conto di Davide Sacchetti
> Inviato: lunedì 12 aprile 2010 13.51
> A: GrADS Users Forum
> Oggetto: Re: [gradsusr] About forecast validity and geographical zone.
> 
> Dear Diego,
> use "grib2ctl.pl -verf <filename>", (grib2ctl was an old shell script)
> 
> about the different geographical areas you should split your grib file
> 
> if this does not help you can contact me directly
> 
> Bye bye
> Davide
> 
> 
> On Fri, 2010-04-09 at 17:51 +0200, Diego Morelli wrote:
> > I have seen that
> > 
> >       * in a grib file there can be more than one grib record and also
> >         that each record can contain information about a validity of
> >         forecast time, or about a geographical zone, different from
> >         the other record. These is also highlighted using wgrib. 
> >       * The grib2ctl issue a descriptor file without information about
> >         forecast validity (doesn’t it?) 
> >       * The grib2ctl issue a descriptor file with geographical
> >         information contained in only one record
> >       * GrADS can show only information descripted in the descriptor
> >         file: It shows only the data correspondent to an internal zone
> >         of the geographical area just setted in the descriptor file
> > 
> >  
> > 
> > My questions are:
> > 
> >  
> > 
> >       * The maps issued by GrADS, at what validity is referred (in the
> >         case of more validity present in a grib file)?
> >       * In the case that I have a file with records referred to more
> >         than one forecast validity, how can I extract the map
> >         correspondent to all validity?
> >       * How can I extract information about all geographical zone
> >         contained in the unique grib file?
> > 
> >  
> > 
> > These are the product I’m using:
> > 
> >  
> > 
> > grib2ctl v0.9.12.5p45
> > 
> > wgrib v1.8.0.12
> > 
> > GrADS Ver. 2.0.a7.1
> > 
> >  
> > 
> > In the attachment, there is an example of the two kind of files I
> > spoke above: file LFPW_70.b is referred to a unic forecast validity of
> > 30 Hours, and cover a geographical zone Lat(-90,90), Lon (-120,150).
> > 
> > The other file contains 2 validity: 12 Hours and 6 Hours
> > 
> >  
> > 
> > Regards,
> > 
> >  
> > 
> > Diego
> > 
> >  
> > 
> > Diego Morelli
> > 
> > T.R.S. S.p.A.
> > 
> > 
> > _______________________________________________
> > gradsusr mailing list
> > gradsusr at gradsusr.org
> > http://gradsusr.org/mailman/listinfo/gradsusr
> 
> 


-- 
Sacchetti Davide
Centro Funzionale Meteo Idrologico di Protezione Civile della Regione Liguria
ARPAL Unità Tecnica Complessa di livello Regionale
V.le Brigare Partigiane 2 16121 Genova (I)
tel: +39 010 6437535                    fax: +39 010 6437520
mail: davide.sacchetti at arpal.org     web: www.meteoliguria.it