interpolating error.

Hi,

After interpolation of ncep-ncar data onto a model grid, the interpolated
and original data don't match up. The number of latitudes, longitudes and
time is the same so basically I just wrote the data under a different
filename. Maybe that's what wrong and I should have applied some special
interpolation function? Or maybe the fields don't match up because in the
NCEP-NCAR reanalysis the dimensions are flipped (lon first, lat second)?

NCEP-NCAR:
lon = 192 ;
lat = 94 ;
time = UNLIMITED ; // (1460 currently)
MODEL forcing:
        lat = 94 ;
lon = 192 ;
time = UNLIMITED ; // (1460 currently)

Below I copied my NCL script and info on the ncep-ncar reanalysis data:

1) NCL CODE:
pacman8 1016% vi write_t2.ncl

  load "$NCARG_ROOT/lib/ncarg/nclex/gsun/gsn_code.ncl"
  load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
  load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
  load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/shea_util.ncl"
  begin
; ------------------ "read data1 file" --------------
i=1979
   a = addfile("air.2m.gauss."+i+".nc","r")
   b = addfile("ncep.t_10.T62."+i+".26JAN2010.nc","w")
   t_10=a->air
  b->t_10=(/t_10/)
 end

2) NCDUMP -H on NCEP-NCAR;

netcdf air.2m.gauss.1979 {
dimensions:
lon = 192 ;
lat = 94 ;
time = UNLIMITED ; // (1460 currently)
variables:
float lat(lat) ;
lat:units = "degrees_north" ;
lat:actual_range = 88.542f, -88.542f ;
lat:long_name = "Latitude" ;
lat:standard_name = "latitude" ;
lat:axis = "Y" ;
float lon(lon) ;
lon:units = "degrees_east" ;
lon:long_name = "Longitude" ;
lon:actual_range = 0.f, 358.125f ;
lon:standard_name = "longitude" ;
lon:axis = "X" ;
double time(time) ;
time:units = "hours since 1-1-1 00:00:0.0" ;
time:long_name = "Time" ;
time:actual_range = 17338824., 17347578. ;
time:delta_t = "0000-00-00 06:00:00" ;
time:avg_period = "0000-00-00 06:00:00" ;
time:standard_name = "time" ;
time:axis = "T" ;
short air(time, lat, lon) ;
air:long_name = "4xDaily Air temperature at 2 m" ;
air:unpacked_valid_range = 150.f, 400.f ;
air:actual_range = 167.6f, 328.7f ;
air:units = "degK" ;
air:add_offset = 477.65f ;
air:scale_factor = 0.01f ;
air:missing_value = 32766s ;
air:precision = 2s ;
air:least_significant_digit = 1s ;
air:GRIB_id = 11s ;
air:GRIB_name = "TMP" ;
air:var_desc = "Air temperature" ;
air:dataset = "NMC Reanalysis" ;
air:level_desc = "2 m" ;
air:statistic = "Mean" ;
air:parent_stat = "Individual Obs" ;
air:valid_range = -32765s, -7765s ;

3) NCDUMP -H ON MODEL forcing data

netcdf ncep.t_10.T62.1971.26JAN2010 {
dimensions:
lat = 94 ;
lon = 192 ;
time = UNLIMITED ; // (1460 currently)
variables:
float lat(lat) ;
lat:long_name = "latitude" ;
lat:units = "degrees_north" ;
float lon(lon) ;
lon:long_name = "longitude" ;
lon:units = "degrees_east" ;
float t_10(time, lat, lon) ;
t_10:long_name = "Air Temperature" ;
t_10:units = "Kelvin" ;
t_10:level = "10m shifted" ;
t_10:sampling_time = "fcst-6" ;
t_10:comment = "FFT of 1958-2000 NCEP time series" ;
t_10:code =
"/home/blackforest/yeager/DAVE/NCEPNY/fft_transform_2D_t10_bmethod.run" ;
t_10:method = "uncorrected; no b-factor added" ;
t_10:_FillValue = -999.f ;

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Received on Thu Apr 25 16:31:10 2013