a. Shell and CDO

Shown below is an example that interpolates one data file from the dpp0016 simulation onto a regular 1°x°1 global grid.

For the interpolation example shown here, a grid description text-file and a weight netcdf-file are needed.

The grid description text-file for an intented 1°x°1 globally grid is as follows:

  # gridID 1
  #
  gridtype  = lonlat
  gridsize  = 64800
  xsize     = 360
  ysize     = 180
  xname     = lon
  xlongname = "longitude"
  xunits    = "degrees_east"
  yname     = lat
  ylongname = "latitude"
  yunits    = "degrees_north"
  xfirst    = -179.95
  xinc      = 1
  yfirst    = -89.95
  yinc      = 1 

Simply create a text file with any text editor, copy and paste the text above into the file and name the file, for example, “griddes_1x1.txt”. It can be convenient to do this only once and keep it for later multiple applications in the users $HOME or $WORK-directory. If the intended grid should be of a different resolution, say 0.1°x0.1°, then the grid discription would be :

  # gridID 1
  #
  gridtype  = lonlat
  gridsize  = 6480000
  xsize     = 3600
  ysize     = 1800
  xname     = lon
  xlongname = "longitude"
  xunits    = "degrees_east"
  yname     = lat
  ylongname = "latitude"
  yunits    = "degrees_north"
  xfirst    = -179.95
  xinc      = 0.1
  yfirst    = -89.95
  yinc      = 0.1 

The weight file can be created using CDO. For this you need the grid description text-file shown above, the ICON grid-file for the native model grid (in this case R2B9 for the dpp0016 simulation) and also one dpp0016 data file is required. The ICON grid-file of the dpp0016 simulation can be found at /pool/data/ICON/grids/public/mpim/0015/icon_grid_0015_R02B09_G.nc. The general structure of the CDO command creating the weight file is:

cdo gendis,grid-description-text-file -setgrid,ICON_grid_file one_dpp0016_data weightfile

For example, storing the output weight file to the $SCRATCH-directory:

cdo gendis,griddes_1x1.txt -setgrid,/pool/data/ICON/grids/public/mpim/0015/icon_grid_0015_R02B09_G.nc /work/mh0287/k203123/GIT/icon-aes-dyw_albW/experiments/dpp0016/dpp0016_atm_2d_ml_20200201T000000Z.nc $SCRATCH/weight_dpp0016_1x1.nc

Now, the interpolation can be done via:

cdo -remap,griddes_1x1.txt,$SCRATCH/weight_dpp0016_1x1.nc /work/mh0287/k203123/GIT/icon-aes-dyw_albW/experiments/dpp0016/dpp0016_atm_2d_ml_20200201T000000Z.nc $SCRATCH/dpp0016_atm_2d_ml_20200201T000000Z_1x1.nc