how to extract data from a huge nc data file?

From: Zhang Tao <Tao.Zhang_at_nyahnyahspammersnyahnyah>
Date: Mon, 23 Jun 2008 12:25:56 -0600

Hi, all,

I have a huge netcdf data file
"thetao_O1.20C3M_1.CCSM.ocnm.1950-01_cat_1999-12.nc" and
  the size is about 12G.

   I want to extract parts of data and generate a small size netcdf
file, the specific command is listed in point 3 below
  and I get the error message "segmentation fault" see point 2 below.
     I can use "ncdump" to look at the attribution of the data, see
point 1 below.

  Does anyone know how to extract data from this huge nc file?

   Thanks,
  Tao
   
  

1)
netcdf thetao_O1.20C3M_1.CCSM.ocnm.1950-01_cat_1999-12 {
dimensions:
        lon = 320 ;
        lat = 395 ;
        depth = 40 ;
        bnds = 2 ;
        time = UNLIMITED ; // (600 currently)
variables:
        double lon_bnds(lon, bnds) ;
        double lat_bnds(lat, bnds) ;
        double depth_bnds(depth, bnds) ;
        double time_bnds(time, bnds) ;
        double lon(lon) ;
                lon:axis = "X" ;
                lon:standard_name = "longitude" ;
                lon:bounds = "lon_bnds" ;
                lon:long_name = "Longitude" ;
                lon:units = "degrees_east" ;
        double lat(lat) ;
                lat:axis = "Y" ;
                lat:standard_name = "latitude" ;
                lat:bounds = "lat_bnds" ;
                lat:long_name = "Latitude" ;
                lat:units = "degrees_north" ;
       double depth(depth) ;
                depth:axis = "Z" ;
                depth:standard_name = "depth" ;
                depth:positive = "down" ;
                depth:units = "m" ;
                depth:bounds = "depth_bnds" ;
        double time(time) ;
                time:calendar = "noleap" ;
                time:standard_name = "time" ;
                time:axis = "T" ;
                time:units = "days since 0000-1-1" ;
                time:bounds = "time_bnds" ;
        float thetao(time, depth, lat, lon) ;
                thetao:comment = "Created using NCL code
CCSM_ocnm_2cf.ncl on\n",
                        " machine mineral" ;
                thetao:missing_value = 1.e+20f ;
                thetao:long_name = "sea_water_potential_temperature" ;
                thetao:cell_methods = "time: mean (interval: 1 month)" ;
                thetao:history = "Interpolated to regular grid from
dipole grid,\n",
                        "TEMP+273.15" ;
                thetao:units = "K" ;
                thetao:original_units = "C" ;
                thetao:original_name = "TEMP" ;
                thetao:standard_name = "sea_water_potential_temperature" ;
                thetao:_FillValue = 1.e+20f ;

2)
---------------------------
/nas/tzhang/ZTIPCC4/ncar_ccsm3_0/20c3m/nc> extract_thetao_20C3M_1.CCSM.csh &
[1] 41886
/nas/tzhang/ZTIPCC4/ncar_ccsm3_0/20c3m/nc> Segmentation fault

[1] Exit 139 extract_thetao_20C3M_1.CCSM.csh
----------------------------------------------------

3)
ncks -c -F -d depth,1,17 -v thetao
thetao_O1.20C3M_1.CCSM.ocnm.1950-01_cat_1999-12.nc
thetao_upper_O1.20C3M_1.CCSM.ocnm.1950-01_cat_1999-12.nc

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Received on Mon Jun 23 2008 - 12:25:56 MDT

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