Re: wind gfs

ok, it works

Thanks

Christelle

2012/5/31 Dennis Shea <shea@ucar.edu>

> As noted by Kyle, if you have a vertical coordinate variable
> then you can use the "natural coordinates" via {...}.
>
> I do not have a copy of the file you are using. The file I have
> is named: gblav.T00Z.PGrbF03.grb
>
> ---
> The 1st rule of data processing is to *always* look at your data file(s).
>
> %> ncl_filedump gblav.T00Z.PGrbF03.grb | less
>
> [snip]
> float UGRD_P0_L103_GLL0 ( lat_0, lon_0 )
> center : US National Weather Service - NCEP (WMC)
> production_status : Operational products
> long_name : U-component of wind
> units : m s-1
> _FillValue : 1e+20
> grid_type : Latitude/longitude
> parameter_discipline_and_**category : Meteorological products,
> Momentum
> parameter_template_discipline_**category_number : ( 0, 0,
> 2, 2 )
> level_type : Specified height level above ground (m)
> level : 10
> forecast_time : 3
> forecast_time_units : hours
> initial_time : 02/03/2012 (00:00)
> [snip]
>
> Note the "level" *attribute*. In this case, You can read the 10m level
> directly.
>
> f = addfile("gblav.T00Z.PGrbF03.**grb", "r")
> u10 = f->UGRD_P0_L103_GLL0
>
> ---
> You can also use NCL's grib file options. The following
> forces NCL the include what it considers 'degenerate
> dimensions' (array size 1) to be included. In the above,
> the level dimension is of size one so it is a
> degenerate dimension.
> setfileoption("grb","**SingleElementDimensions","**level")
> f = addfile("gblav.T00Z.PGrbF03.**grb", "r")
>
> u = f->UGRD_P0_L103_GLL0
> printVarSummary(u)
>
> Variable: u
> Type: float
> Total Size: 1039680 bytes
> 259920 values
> Number of Dimensions: 3
> Dimensions and sizes: [lv_HTGL16 | 1] x [lat_0 | 361] x [lon_0 | 720]
> Coordinates:
> lv_HTGL16: [10..10] <******************** Note
> lat_0: [90..-90]
> lon_0: [ 0..359.5]
> Number Of Attributes: 12
> center : US National Weather Service - NCEP (WMC)
> production_status : Operational products
> long_name : U-component of wind
> units : m s-1
> _FillValue : 1e+20
> grid_type : Latitude/longitude
> parameter_discipline_and_**category : Meteorological products, Momentum
> parameter_template_discipline_**category_number : ( 0, 0, 2, 2 )
> level_type : Specified height level above ground (m)
> forecast_time : 3
> forecast_time_units : hours
> initial_time : 02/03/2012 (00:00)
>
> Here you could use the {...} because there is a 'coordinate variable'
> named 'level'
>
> u10 = u({10},:,:)
>
> or, directly
>
> u10 = f->UGRD_P0_L103_GLL0({10},:,:)
>
> printVarSummary(u10)
>
>
>
> On 5/31/12 5:52 AM, Kyle Griffin wrote:
>
>> Christelle,
>>
>> To reference a specific value of a coordinate array, you need to place
>> the coordinate in curly braces. This tells it to look for the value of
>> that coordinate variable instead of the index of that coordinate
>> variable. In your case, the vertical coordinate of the XXXX_P0_L103_GLL0
>> variables are (/10,80,100/) - so what you do right now is try and refer
>> to the 11th index of that 3-value array, which is clearly out of bounds.
>> You'll want to change your statements to look like:
>>
>> UGRD_P0_L103_GLL0({10},:,:)
>> VGRD_P0_L103_GLL0({10},:,:)
>>
>> To read more on the variable subscripting, see this section of the NCL
>> Language Guide:
>> http://www.ncl.ucar.edu/**Document/Manuals/Ref_Manual/**
>> NclVariables.shtml<http://www.ncl.ucar.edu/Document/Manuals/Ref_Manual/NclVariables.shtml>
>>
>>
>> Kyle
>> ------------------------------**-----------------------
>> Kyle S. Griffin
>> Dept. of Atmospheric and Environmental Sciences
>> University at Albany, SUNY
>> 1400 Washington Ave, Albany, NY 12222
>> Office: ES-218 Email: kgriffin@albany.edu <mailto:kgriffin@albany.edu>
>>
>> http://www.atmos.albany.edu/**student/kgriffin/<http://www.atmos.albany.edu/student/kgriffin/>
>>
>>
>>
>> On Thu, May 31, 2012 at 4:37 AM, Christelle LACROIX <cl@meteoconsult.fr
>> <mailto:cl@meteoconsult.fr>> wrote:
>>
>> Hi,
>>
>>
>> I tried to plot wind 10m above ground from gfs datas, i
>> use UGRD_P0_L103_GLL0 and VGRD_P0_L103_GLL0, but when i write
>>
>> UGRD_P0_L103_GLL0(10,:,:)
>> VGRD_P0_L103_GLL0(10,:,:)
>>
>> i have some errors
>>
>> /datas/grib/gfs/18/gblav.T18Z.**PGrbF06.grb
>> 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.
>> warning: Entry (224) not found in code table file
>> /usr/local/src/ncl/lib/ncarg/**grib2_codetables/ncep/4/4.2.0.**2.table
>> warning: NclGRIB2: codetable file
>> "/usr/local/src/ncl/lib/ncarg/**grib2_codetables/ncep/4/4.2.2.**
>> 4.table"
>> not a valid GRIB2 code table.
>> warning: Entry (2) not found in code table file
>> /usr/local/src/ncl/lib/ncarg/**grib2_codetables/ncep/4/4.2.**table
>> fatal:Subscript out of range, error in subscript #0
>>
>>
>> Do you have an idea to help me , please?
>>
>>
>> Thanks
>>
>> CL
>>
>>
>>
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Received on Thu May 31 08:18:46 2012