[gradsusr] lats4d grib convertion problem

[Arlindo da Silva]

2011/8/30 A. S. <irln at hotmail.com>

>  Hello,
> I'm having some problem with cropping and subsetting GRIB files.
> I found lats4d script very useful for that, but there is some annoying
> error it makes - in the resulting GRIB file it writes the wrong variable
> names (while in the resulting CTL file they are correct).
>
> For example, I'm taking the lfff00120000p GRIB file (attached, together
> with its CTL and IDX),
> and it has 5 fields inside: fi, omega, relhum, t, u, v.
> You can see it in the attached lfff00120000p.ctl file, as well as by
> running "wgrib lfff00120000p".
> Then I'm trying to extract only 2 fields, e.g. fi and t, to reduce the
> domain size, and t! o dump the result into a new GRIB file.
> To do that, I'm using the following command:
>
>  lats4d.sh -i lfff00120000p.ctl -o lfff00120000p_crop.grb -format
> grads_grib -lat 29 33.5 -lon 34 36 -vars fi t
>
> This command generates 3 new files: lfff00120000p_crop.grb, lfff00120000p_crop.ctl
> and lfff00120000p_crop.gmp (attached as well).
> The resulting GRIB file seems to be valid, and the CTL file looks
> absolutely fine!
> But when I try to run "wgrib lfff00120000p_crop.grb", instead of fi & t, I
> see PRES & PRMSL** variables!
> My guess is, that the lats4d script is in some way unaware of the fact that
> the original GRIB file is encoded according to Offenbach (center code 78)
> GRIB table, but I don't know how to define it.
>
> Any help would be highly appreciated!
> Thanks!
> Alon.
>

You may need to setup a LATS PARAMETER TABLE for your file; enter

% lats4d.sh -h

and read the section on LATS PARAMETER TABLES. Please notice that the LATS
documentation page is no longer available at PCMDI. Use the way back machine
instead:

http://web.archive.org/web/20080920122353/http://www-pcmdi.llnl.gov/software/lats/

  Arlindo



>
> P. S. some aditional technical info, don't know if it's relevant:
> lats4d Version 2.1.5
> Grads v2.0.a9.oga.1
> Ubuntu 10.04 x86_64
>
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>
>


-- 
Arlindo da Silva
dasilva at alum.mit.edu
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