[gradsusr] Reading CMIP5 GCM data with GrADS

[itesh dash]

Dear All,

I am trying to read the CMIP5 HADGEM-AO GCM (nc file) data sets using
grads. I have prepared a descriptor file. However, it seems the file is not
read correctly, and I receive wrong temperature values.

The GCM attributes are:

netcdf tasmax_day_HadGEM2-AO_rcp45_r1i1p1_20060101-21001230 {
dimensions:
time = UNLIMITED ; // (34200 currently)
lat = 145 ;
lon = 192 ;
bnds = 2 ;
variables:
double time(time) ;
time:bounds = "time_bnds" ;
time:units = "days since 2006-01-01" ;
time:calendar = "360_day" ;
time:axis = "T" ;
time:long_name = "time" ;
time:standard_name = "time" ;
double time_bnds(time, bnds) ;
double lat(lat) ;
lat:bounds = "lat_bnds" ;
lat:units = "degrees_north" ;
lat:axis = "Y" ;
lat:long_name = "latitude" ;
lat:standard_name = "latitude" ;
double lat_bnds(lat, bnds) ;
double lon(lon) ;
lon:bounds = "lon_bnds" ;
lon:units = "degrees_east" ;
lon:axis = "X" ;
lon:long_name = "longitude" ;
lon:standard_name = "longitude" ;
double lon_bnds(lon, bnds) ;
double height ;
height:units = "m" ;
height:axis = "Z" ;
height:positive = "up" ;
height:long_name = "height" ;
height:standard_name = "height" ;
float tasmax(time, lat, lon) ;
tasmax:standard_name = "air_temperature" ;
tasmax:long_name = "Daily Maximum Near-Surface Air Temperature" ;
tasmax:comment = "daily-maximum near-surface (usually, 2 meter) air
temperature." ;
tasmax:units = "K" ;
tasmax:original_name = "TASMAX" ;
tasmax:cell_methods = "time: maximum (interval: 1.000000 days)" ;
tasmax:cell_measures = "area: areacella" ;
tasmax:history = "2012-10-29T09:05:42Z altered by CMOR: Treated scalar
dimension: \'height\'. 2012-10-29T09:05:42Z altered by CMOR: replaced
missing value flag (-1.07374e+09) with standard missing value (1e+20)." ;
tasmax:coordinates = "height" ;
tasmax:missing_value = 1.e+20f ;
tasmax:_FillValue = 1.e+20f ;
tasmax:associated_files = "baseURL:
http://cmip-pcmdi.llnl.gov/CMIP5/dataLocation gridspecFile:
gridspec_fx_HadGEM2-AO_rcp45_r0i0p0.nc areacella:
areacella_fx_HadGEM2-AO_rcp45_r0i0p0.nc" ;

// global attributes:
:institution = "NIMR (National Institute of Meteorological Research, Seoul,
South Korea)" ;
:institute_id = "NIMR-KMA" ;
:experiment_id = "rcp45" ;
:source = "HadGEM2-AO r6.6.3 (2010): atmosphere:  HadGAM (HadGAM2, N96L38);
atm: HadGOM (HadGOM2, 1x1L40, increased res at Equator); sea ice: part of
HadGOM2; land: MOSES-2" ;


The descriptor (.ctl) file :

DSET ^tasmax_day_HadGEM2-AO_rcp45_r1i1p1_20060101-21001230.nc
TITLE Air Temperature
DTYPE netcdf
OPTIONS 365_day_calender
UNDEF 1.e+20f
xdef 192 linear 0 1.875
ydef 145 linear -90 1.25
zdef 1 levels 1013.0
tdef 34200 linear 00Z1Jan2006 1dy
VARS 1
tasmax 1 t,z,y,x Air Temperature [K]
ENDVARS



Kindly, help in understanding where we are doing wrong.

Much appreciate your help in this.


Regards,
Itesh Dash
RIMES
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