[Met_help] Input data for point-stat tool
capecchi
v.capecchi at ibimet.cnr.it
Fri Sep 26 04:49:54 MDT 2008
John,
even if in a narrow way I was successful in converting my NetCDF files to
GRIB1 format...in the followings lines
the commands I'm using in the terminal:
cdo selcode,-2 my_netcdf_file tmp1
cdo expr,'tmpk=ta2m+273.15;' ftmp1 ftmp2
cdo -f grb setcode,011 ftmp2 my_grib1_file
some of the previous operations are redundant but since I'm mostly
interested in 2 meters
temperature the method with cdo is quite fast even with large amount of
data.
I wish I was able to use a GRIB user defined table for converting all the
parameters in my NetCDF file
and with just this command:
cdo -t my_user_defined_table -f grb copy
<http://aaa.meteosalute_2007123100-2008010223_d01.nc/>my_netcdf_file
my_grib1_file
but, unfortunately, it was not possible and none change was performed.
Anyway I'm shyly suggesting the use of cdo operators for this task until the
introduction of NetCDF files as input file
for MET tool.
Thanks for your help, Valerio
2008/9/25 John Halley Gotway <johnhg at rap.ucar.edu>
> Valerio,
>
> Sorry, no. I don't have any experience using "cdo". I'll be interested to
> hear if you're successful using it.
>
> John
>
> capecchi wrote:
> > John,
> > thanks very much for your help, I decided to convert my NetCDF file to
> GRIB1
> > file
> > using `cdo -f grb copy ...` command...do you have any (...) about known
> > problems with this
> > procedure?
> > Anyway I hope version 2.0 of MET will accept general format of NetCDF
> files.
> > Thanks again, bye, Valerio
> >
> > 2008/9/23 John Halley Gotway <johnhg at rap.ucar.edu>
> >
> >> Valerio,
> >>
> >> I do think that it would be reasonable to massage your NetCDF files into
> a
> >> format that METv1.1 would read. However, METv1.1 is only compatible
> with a
> >> rather rigid format of NetCDF at this point. For
> >> the next release of MET, version 2.0, we're planning to support a more
> >> general format of NetCDF.
> >>
> >> Currently, MET expects gridded NetCDF data to abide by the following
> >> conventions:
> >>
> >> (1) dimensions named "lat" and "lon" define the dimension of the data.
> >> (2) variables have only two dimensions, "lat" and "lon".
> >> (3) variables are named using the GRIB code abbreviation for the GRIB
> field
> >> they represent and are in the units prescribed by that GRIB code. For
> >> example, a variable containing accumulated
> >> precipitation would be named "APCP" (GRIB code abbreviation) and its
> units
> >> would be millimeters.
> >> (4) several variable attributes are required to define the
> initialization,
> >> valid, and accumulation (if applicable) times.
> >> (5) global attributes defining the grid on which the data resides must
> be
> >> defined.
> >>
> >> The definition of the grid in (5) is necessary to perform conversions
> >> between lat/lon and grid x/y.
> >>
> >> I've attached a sample output file from PCP-Combine. This example
> contains
> >> data on a lat/lon grid - which I'm guessing is the projection your data
> is
> >> on. The attached file that ends in ".dump" is
> >> just a dump of the NetCDF header. In that file, please note the
> following:
> >>
> >> (1) The "lat" and "lon" dimensions are defined.
> >> (2) The variable named APCP contains accumulated precipitation in mm.
> The
> >> GRIB codes and corresponding abbreviations are defined here:
> >> http://www.nco.ncep.noaa.gov/pmb/docs/on388/table2.html
> >> (3) The APCP variable contains the several attributes, but only the
> >> following are actually read by the code: level, init_time_ut,
> valid_time_ut,
> >> and accum_time (if not applicable, just set to 0).
> >> The "_ut" is for unixtime, or seconds since January 1, 1970.
> >> (4) Global attributes defining the projectsion:
> >> :Projection = "LatLon" ;
> >> :lat_ll_deg = "25.063000 degrees_north" ;
> >> :lon_ll_deg = "-124.938000 degrees_east" ;
> >> :delta_lat_deg = "0.125000 degrees" ;
> >> :delta_lon_deg = "0.125000 degrees" ;
> >> :Nlat = "224 grid_points" ;
> >> :Nlon = "464 grid_points" ;
> >> Here you'll just insert your grid definition info.
> >>
> >> Hope that helps, and feel free to write with more questions about this.
> >>
> >> John Halley-Gotway
> >> johnhg at ucar.edu
> >>
> >>
> >> capecchi wrote:
> >>> Dear met_help,
> >>> I'm currently involved in WRF verification issues for a
> biometeorological
> >>> service in Italy.
> >>> I'm interested in point-stat tools but I have, as input forecast data,
> >>> NetCDF files derived and post-elaborated from WRF GRIB1 output.
> >>> I read from MET User Guide that I'm supposed to provide as input data
> >> only
> >>> GRIB1 files or NetCDF format
> >>> that is output from the Pcp-Combine tool; I'm wondering if my NetCDF
> file
> >>> format are like the Pcp-Combine tool's format
> >>> (I'm attaching one as sample) or if you can suggest me some NetCDF to
> >> GRIB1
> >>> converter tools (like cdo, nco, or...)
> >>> Thanks in advance for any help you can give me, regards, Valerio
> Capecchi
> >>>
> >>>
> >>
> **************************************************************************
> >>> Valerio Capecchi
> >>>
> >>>
> >>
> --------------------------------------------------------------------------
> >>> Interdepartemental Centre of Bioclimatology - University of Florence
> >>> Piazzale delle Cascine 18
> >>> 50144 Firenze. Italia
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> >>> Fax: +39 055332472
> >>>
> >>> WEB http://www.unifi.it/cib
> >>>
> >>
> ---------------------------------------------------------------------------
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> >> Modelling)
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> >>>
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> >>>
> >>
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> >>
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> >>>
> >>>
> >>>
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> >>>
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> >> netcdf nam.20070330.ncep110 {
> >> dimensions:
> >> lat = 224 ;
> >> lon = 464 ;
> >> variables:
> >> float lat(lat, lon) ;
> >> lat:units = "degrees_north" ;
> >> lat:long_name = "Latitude" ;
> >> lat:_FillValue = -9999.f ;
> >> float lon(lat, lon) ;
> >> lon:units = "degrees_east" ;
> >> lon:long_name = "Longitude" ;
> >> lon:_FillValue = -9999.f ;
> >> float APCP(lat, lon) ;
> >> APCP:grib_code = 61 ;
> >> APCP:units = "kg/m^2" ;
> >> APCP:long_name = "Total precipitation" ;
> >> APCP:level = "SFC" ;
> >> APCP:_FillValue = -9999.f ;
> >> APCP:init_time = "20070330_000000" ;
> >> APCP:init_time_ut = 1175212800 ;
> >> APCP:valid_time = "20070331_120000" ;
> >> APCP:valid_time_ut = 1175342400 ;
> >> APCP:accum_time = "6 hours" ;
> >>
> >> // global attributes:
> >> :FileOrigins = "File
> /home/johnhg/nam.20070330.ncep110.ncgenerated 20080923_163157 UTC on host
> billiken by the PCP-Combine tool" ;
> >> :RunCommand = "Addition:
> >> /home/johnhg/nam.20070330.ncep110.grb with accumulation of 3 hours plus
> >> /home/johnhg/nam.20070330.ncep110.grb with accumulation of 3 hours." ;
> >> :Projection = "LatLon" ;
> >> :lat_ll_deg = "25.063000 degrees_north" ;
> >> :lon_ll_deg = "-124.938000 degrees_east" ;
> >> :delta_lat_deg = "0.125000 degrees" ;
> >> :delta_lon_deg = "0.125000 degrees" ;
> >> :Nlat = "224 grid_points" ;
> >> :Nlon = "464 grid_points" ;
> >> }
> >>
> >>
> >
> >
> > ------------------------------------------------------------------------
> >
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> > Met_help at mailman.ucar.edu
> > http://mailman.ucar.edu/mailman/listinfo/met_help
>
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