[ncl-talk] problem with bilinear interpolation

[antonio avio]

Hi Karin,
What I wanted to do is to interpolate from 144x288 to 73x144.
It works, but the edges of the data are missing esp. in the north and south
poles.
Thanks

On Thu, Apr 2, 2015 at 12:56 PM, Karin Meier-Fleischer <
meier-fleischer at dkrz.de> wrote:

>  Hi Antonio,
>
> I think you should have a look at you lines
>
>   xlat = fspan(-90.,90,73)
>   xlon = fspan(0.,357.5,144)
>
> you're mixing latitude and longitude and/or use wrong dimension sizes.
>
>   xlat = fspan(-90.,90,144)
>   xlon = fspan(0.,357.5,288)
>
> Bye,
> Karin
>
> Am 02.04.15 um 12:44 schrieb antonio avio:
>
>   Hallo NCL,
>  Im just wondering why the output of the interpolation filed are missing
> in the last latitude (south and north poles: 87.5-90). The input data is
> bellow:
>
> netcdf MERRA.U.1979.plev {
> dimensions:
>         time = 365 ;
>         levels = 42 ;
>         latitude = 144 ;
>         longitude = 288 ;
> variables:
>         float U(time, levels, latitude, longitude) ;
>                 U:long_name = "Eastward wind component" ;
>                 U:_FillValue = 1.e+15f ;
>                 U:comments = "Unknown1 variable comment" ;
>                 U:grid_name = "grid-1" ;
>                 U:time_statistic = "average" ;
>         double time(time) ;
>                 time:standard_name = "time" ;
>                 time:units = "hours since 1979-01-01 12:00:00" ;
>                 time:calendar = "standard" ;
>         double levels(levels) ;
>                 levels:standard_name = "air_pressure" ;
>                 levels:long_name = "Level" ;
>                 levels:units = "hPa" ;
>                 levels:positive = "down" ;
>                 levels:axis = "Z" ;
>         double latitude(latitude) ;
>                 latitude:standard_name = "latitude" ;
>                 latitude:long_name = "Latitude" ;
>                 latitude:units = "degrees_north" ;
>                 latitude:axis = "Y" ;
>         double longitude(longitude) ;
>                 longitude:standard_name = "longitude" ;
>                 longitude:long_name = "Longitude" ;
>                 longitude:units = "degrees_east" ;
>                 longitude:axis = "X" ;
>
>
>  My script is:
>
> oad "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
>
> begin
>
> ;===========2.5x2.5=============
>
>   xlat = fspan(-90.,90,73)
>   xlon = fspan(0.,357.5,144)
>   xlat at units = "degrees_north"
>   xlon at units = "degrees_east"
>
> ;===============================
>
> do y =1979,1979
>   print(y)
>
>   f  = addfile ("MERRA.U."+y+".plev.nc" , "r")
>
>     u   = f->U
>     u   = lonFlip(u)
>
> printVarSummary(u)
>
> print("=====================Process=========================")
>
>   U = linint2(u&longitude,u&latitude,u,True,xlon,xlat,0)
>
>
>   U!0   = "time"
>   U!1   = "level"
>   U!2   = "lat"
>   U!3   = "lon"
>   U&lat = xlat
>   U&lon = xlon
>   U&time  = u&time
>   U&level = u&levels
>
>  printVarSummary(U)
>
>  Thank you
>
>
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>
> --
> Dipl. Geophys. Karin Meier-Fleischer
> Visualization
> Application Support
>
> Deutsches Klimarechenzentrum GmbH (DKRZ)
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>
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>
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