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Christopher Bull

Aspiring Oceanographer at the British Antarctic Survey. Big data python enthusiast. Outdoor adventurer.

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Building the initial state and forcing fields for WED12.

Suggested reading:

Build the bathymetry (and ice shelf draft if needed) and coordinates files for the regional domain. Go to your repo, and update the following file for your machine: vi BUILD_CONFIG_NEMO/ (in the ARCHER case this was unnecessary).

./extract_bathy_coord   ## -> should create the bathy and coordinate files,
                        ##    e.g. and
                        ##    (stored in directory defined as config_dir in the namelist)

Build the mesh mask

Prerequisite: successful compile of NEMO (see Step 3).

Create mesh_mask file.

To do this, you need to run nemo.exe to calculate the exact mesh and mask. Run nemo with nn_msh = 1 in the namelist. No need to have all the input files here, just: xios_files, namelists,, and It will crash shortly after creating Details:

mkdir -p /fs2/n02/n02/chbull/nemo/run/create_mesh_mask_wed12
cd /fs2/n02/n02/chbull/nemo/run/create_mesh_mask_wed12
ln -s /fs2/n02/n02/chbull/nemo/bld_configs/input_WED12/
ln -s /fs2/n02/n02/chbull/nemo/bld_configs/input_WED12/
ln -s /fs2/n02/n02/chbull/nemo/bld_configs/input_WED12/ 
ln -s /fs2/n02/n02/chbull/nemo/models/XIOS/bin/xios_server.exe xios_server.exe
ln -s /fs2/n02/n02/chbull/nemo/models/dev_r5518_GO6_package/NEMOGCM/CONFIG/WED12/BLD/bin/nemo.exe nemo.exe
#cp namelist_ref AND namelist_cfg into create_mesh_mask_wed12 folder
#cp namelist_ice_ref AND namelist_ice_cfg into create_mesh_mask_wed12 folder

#grab any xios2 files just so the model will start, e.g.
cp /fs2/n02/n02/chbull/nemo/models/dev_r5518_GO6_package/NEMOGCM/CONFIG/GYRE_XIOS/EXP00/iodef.xml /fs2/n02/n02/chbull/nemo/run/create_mesh_mask_wed12_two/
cp /fs2/n02/n02/chbull/nemo/models/dev_r5518_GO6_package/NEMOGCM/CONFIG/SHARED/field_def.xml /fs2/n02/n02/chbull/nemo/run/create_mesh_mask_wed12_two/
cp /fs2/n02/n02/chbull/nemo/models/dev_r5518_GO6_package/NEMOGCM/CONFIG/GYRE_XIOS/EXP00/file_def.xml /fs2/n02/n02/chbull/nemo/run/create_mesh_mask_wed12_two/
cp /fs2/n02/n02/chbull/nemo/models/dev_r5518_GO6_package/NEMOGCM/CONFIG/GYRE_XIOS/EXP00/domain_def.xml /fs2/n02/n02/chbull/nemo/run/create_mesh_mask_wed12_two/

## NB: set jpni=jpnj=jpnij=0 in the &nammpp section of NEMO's namelist.
##     and use the same &namdom parameters as in the simulation used as BDYs.
qsub    ## this will create mesh_mask_${CONFIG}.nc before crashing

In my ARCHER case the file looks like:

#PBS -N PC-eos80
#PBS -l walltime=1:00:00
#PBS -l select=1
#PBS -j oe
#PBS -A n02-bas

export PBS_O_WORKDIR=$(readlink -f $PBS_O_WORKDIR)               

aprun -n 2 ./nemo.exe
aprun -n 2 ./xios_server.exe

This should result in and out of this (check that mbathy, misf, isfdraft look sensible). We now need to stick them back together…

cd /fs2/n02/n02/chbull/nemo/run/create_mesh_mask_wed12
#From BUILD_CONFIG_NEMO, make sure NEMOdir is correct
mv $WORKDIR/input/nemo_${CONFIG}/mesh_mask_${CONFIG}.nc ## directory defined as config_dir

Create the inital state

Create the initial state (temperature and salinity)

./extract_istate            ## -> should create the initial state for temperature and salinity
                            ##    e.g. and
                            ##    (stored in directory defined as config_dir in the namelist)

Ocean forcing files

Create the lateral boundary conditions (u, v, T, S, SSH, sea-ice thic, sea-ice frac)

./build_coordinates_bdy       ## -> creates the coordinate file for lateral boundaries
                              ##    e.g.

./extract_bdy_gridT           ## -> creates T,S bdy files and store them in a BDY folder
                              ##    itself located in directory defined as config_dir

./extract_bdy_gridU           ## -> creates U   bdy files and store them in a BDY folder
./extract_bdy_gridV           ## -> creates V   bdy files and store them in a BDY folder
./extract_bdy_icemod          ## -> creates ice bdy files and store them in a BDY folder
./extract_bdy_ssh             ## -> creates SSH bdy files and store them in a BDY folder

./   ## Edit this file first.
                              ## -> concatenate the bdy files into yearly files

./extract_bdy_tides           ## if you want to put tidal signals along the BDYs

Interpolate CICE onto NEMO

If necessary, interpolate CICE onto NEMO grid before running ./extract_bdy_icemod (above). We use CDO to do a linear interpoation. Here’s an example:

#hack up a griddes file so the source file looks more like the target..
cdo griddes > new_grid.txt
cdo griddes > old_grid.txt

#xname/yname as nav_lon/nav_lat (the latter seems to be important to match the target x/y names)
sed -i -e 's/TLON/nav_lon/g' old_grid.txt
sed -i -e 's/TLAT/nav_lat/g' old_grid.txt

#remove area from new_grid.txt, the following will help find it.
#grep –n “[a-d][f-z] new_grid.txt 

#re-write with hacked grid defn
cdo setgrid,old_grid.txt -select,name=aice,hi,hs ../ ./

#Re-mapping, creating the weights first.. 
cdo gennn,new_grid.txt
cdo remap,new_grid.txt,

#copy interpolated data to a G07 file and match LIM variable names according to BUILD_CONFIG_NEMO/src/extract_bdy_icemod.f90

Other files (SSS for restoring, runoff, chlorophyll)

./extract_SSS_restoring       ## -> creates SSS files and store them in a SSS folder
./   ## Edit this file first.
                              ## -> concatenate the bdy files into yearly files

./extract_runoff_icebergs     ## -> creates iceberg runoff file
                              ##    (stored in config_dir defined in the namelist)

./extract_chloro              ## -> creates chlorophyll file
                              ##    (stored in config_dir defined in the namelist)

Atmospheric forcing files

Weights for the interpolation of atmospheric forcing

# here it is assumed that you have NEMO downloaded and installed as explained in step #1
maketools -m X64_ADA -n WEIGHTS           ## Adapt for any machine different from ADA (try makenemo -h)
cd WEIGHTS                                ## See nice README file in this directoy.
cp -p nocsutil/namelist_example_bilin namelist_WEIGHTS_${CONFIG}_bilin ## Edit this namelist

NB: you may have to increase char_len in src/kinds_mod.f90 if you include long path for file names.

Below is an example for namelist_WEIGHTS_${CONFIG}_bilin:

    input_file = ''
    nemo_file = ''
    datagrid_file = ''
    nemogrid_file = ''
    method = 'regular'
    input_lon = 'LON'
    input_lat = 'LAT'
    nemo_lon = 'glamt'
    nemo_lat = 'gphit'
    nemo_mask = 'none'
    nemo_mask_value = 10
    input_mask = 'none'
    input_mask_value = 10

    num_maps = 1
    grid1_file = ''
    grid2_file = ''
    interp_file1 = ''
    interp_file2 = ''
    map1_name = 'data to nemo bilin Mapping'
    map2_name = 'nemo to data bilin Mapping'
    map_method = 'bilinear'
    normalize_opt = 'frac'
    output_opt = 'scrip'
    restrict_type = 'latitude'
    num_srch_bins = 90
    luse_grid1_area = .false.
    luse_grid2_area = .false.

    input_file = ""
    interp_file = ""
    input_name = "snow"
    input_start = 1,1,1,1
    input_stride = 1,1,1,1
    input_stop = 0,0,0,1
    input_vars = 'initial_time0_hours'

    output_file = ""
    output_mode = "create"
    output_dims = 'x', 'y', 'time_counter'
    output_scaling = "snow|1.0", "time_counter|86400.0"
    output_name = 'snow'
    output_lon = 'x'
    output_lat = 'y'
    output_vars = 'time_counter'
    output_attributes = 'time_counter|units|seconds since 1995-00-00 00:00:00',

Then, execute these things:

#create links to relevant input files -> /fs2/n02/n02/chbull/nemo/bld_configs/input_WED12/ -> /fs2/n02/n02/chbull/nemo/bld_configs/input_WED12_mathiot_eORCA025-GO7/ -> /fs2/n02/n02/chbull/nemo/bld_configs/input_WED12_mathiot_eORCA025-GO7/

./scripgrid.exe   ## namelist_${CONFIG}_bilin
./scrip.exe       ## namelist_${CONFIG}_bilin
./scripshape.exe  ## namelist_${CONFIG}_bilin

Then create another namelist: namelist_${CONFIG}_bicub and just change these parameters:

interp_file1 = ''
interp_file2 = ''
map1_name = 'data to nemo bicubic Mapping'
map2_name = 'nemo to data bicubic Mapping'
map_method = 'bicubic'
interp_file = ''
output_file = ''

Then execute :

./scrip.exe       ## namelist_${CONFIG}_bicub
./scripshape.exe  ## namelist_${CONFIG}_bicub

At the end of this, you should have: and

In category: nemo