[gradsusr] GrADS problem

[Arlindo da Silva]

Jessica,

GrADS does not perform automatic regridding. If the 2 files have different
lat/lon grids you won't be able to subtract them unless you regrid one of
the variables. You forgot to tell us the version of GrADS you are running,
so I am sure if you are using opengrads or not. If using opengrads you
should use the re() <http://opengrads.org/doc/udxt/re/> function with box
averaging to remap the higher resolution variable to the grid of the lower
resolution.

The COLA releases come with a linear interpolation function lterp()
<http://grads.iges.org/grads/gadoc/gradfunclterp.html>that performs
bilinear interpolation. Given that your variable is soil temperature, I'd
not recommend linear interpolation in this case, but for a quick plot it
should be OK.

   Arlindo


On Mon, Nov 7, 2011 at 12:57 PM, jessica falzon
<jessica.falzon91 at gmail.com>wrote:

> Hello. I am Jessica and I really appreciate if you help me solve this
> problem.
>
> I am running GrADS on LINUX
>
> I am trying to do a bias of a measured file (08225.30yr.mean.stat.pp.nc)
> and a referenced file (8225_ESRL_1960-1990.nc). The problem is that
> although I am defining the latitude and longitude, an error occurs stating
> that the grids do not match.
>
> The red part is the error output of GrADS.
>
> ga -> sdfopen 8225_ESRL_1960-1990.nc
> Scanning self-describing file: 8225_ESRL_190-1990.nc
> SDF file 8225_ESRL_1960-1990.nc is open as file1
> LON set to 84.375 165
> LAT set to -48.5705 21.9044
> LEV set to 0 0
> Time values set: 1960:1:1:0 1960:1:1:0
> E set to 1 1
> ga -> sdfopen 08225.30yr.mean.stat.pp.nc is open as file 2
> ga -> q file1
> File 1: Monthly NOAA-CIRES 20th century Reanalysis V2
>            Descriptor : 8225_ESRL_1960-1990.nc
>            Binary: 8225_ESRL_1960-1990.nc
>            Type = Gridded
>            Xsize=44 Ysize=38 Zsize=1 Tsize=373 Esize=1
>            Number of variables = 1
>            tsoil 1 t.z.y,x Monthly Soil Temperature
> ga -> q file2
> File 2: Descriptor: 08225.30yr.mean.stat.pp.nc
>           Binary: 08225.30yr.mean.stat.pp.nc
>           Type = Gridded
>           Xsize=174 Ysize=150 Zsize=1 Tsize=1 Esize=1
>            Number of variables = 1
>           soiltemp 1 t.z.y,x Soil Temperature (levels 2,3,4)
> ga -> set gxout grfill
> ga -> set lat -48.5705 21.9044
> LAT set to -48.5705 21.9044
> ga -> set lon 84.375165
> LON set to 84.375165
> ga -> set gxout grfill
> ga -> run bluewhitered
> Enter Min,interval,num of intervals, center
> -5 1 12
> ga -> d soiltemp.2 - tsoil.1
> Data Request Warning: Request is completely outside file limits
> Entire grid contents are set to missing data
> Grid limits of file: X=1 174 Y-1 150 Z= 1 1 T=1 1 E =1 1
> Grid limits of request: X = -167 17 Y=-8 153 Z = 0 0 T = -7511039 -7511039
> E = 1 1
> Warning issued for variable = soiltemp. 2
> Operation error: Incompatable grids
> Dimension ranges aren't equivalent
> Dimension = 0
> 1st grid range = -167 17 2nd = 1 44
> Error ocurred at column 19
> Expression = soiltemp.2 - tsoil.1
>
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>
>


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