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Contents:

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The description on this page follows on from the previous part of the user guide for the OpenIFS 48r1 global 3D forecasting model. It is assumed that the model has been extracted, built and tested on your local computing system. If you have not done this please prefer to the previous part Getting started. 

Set up a forecast experiment

An example forecast experiment has been prepared for OpenIFS 48r1. The experiment ID is  ab2a. 

You should first download the tarball for this example experiment from here: https://sites.ecmwf.int/openifs/openifs-data/case_studies/48r1/karl/ab2a.tar.gz

Extract the example forecast experiment ab2a.tar.gz into a folder in a location suitable for model experiments. The global OpenIFS configuration file (oifs-config.edit_me.sh) sets the variable OIFS_EXPT which should point to the root directory for your OpenIFS experiments. You should extract ab2a.tar.gz to this location, and this folder will become your experiment directory. 

Set up a forecast experiment

An example forecast experiment has been prepared for OpenIFS 48r1. The experiment ID is  ab2a. 

Extract the example forecast experiment ab2a.tar.gz into a folder in a location suitable for model experiments. The global OpenIFS configuration file (oifs-config.edit_me.sh) sets the variable OIFS_EXPT which should point to the root directory for your OpenIFS experiments. You should extract ab2a.tar.gz to this location, and this folder will become your experiment directory. 

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On the ECMWF hpc2020 our model has been previously installed to $OIFS_HOME which is in $HOME/openifs-48r1.1. For the experiment we extract the ab2a package to to $OIFS_EXPT which is in a different location on the file system. The experiment directory shall therefore be $OIFS_EXPT/ab2a/2016092500. EXPT/ab2a/2016092500. 

You can download the ab2a.tar.gz package either using a web browser via the URL in the box below or you could the wget utility as shown below:

cd $OIFS_EXPT
wget https://sites.ecmwf.int/openifs/openifs-data/case_studies/48r1/karl/# download the experiment tarball and extract to the experiment folder:
cp ab2a.tar.gz $OIFS_EXPT
tar -xvzf ab2a.tar.gz

Ensure the namelist files for the atmospheric model (fort.4) and for the wave model (wam_namelist) are found in the experiment directory.  If they are not already there then you can find them in a subfolder (called ecmwf) inside the experiment directory.

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#--- required variables for this experiment:

OIFS_EXPID="ab2a"       # your experiment ID
OIFS_RES="255"          # the spectral grid resolution (here: T255)
OIFS_GRIDTYPE="l"       # the grid type, either 'l' for linear reduced grid, or 'o' for the cubic octahedral grid
OIFS_NPROC=8            # the number of MPI tasks
OIFS_NTHREAD=4          # the number of OpenMP threads
OIFS_PPROC=true         # enable postprocessing of model output after the model run
OUTPUT_ROOT=$(pwd)      # folder where pproc output is created (only used if OIFS_PPROC=true). In this case an output folder is created in the experiment directory.
LFORCE=true             # overwrite existing symbolic links in the experiment directory
LAUNCH=""               # the platform specific run command for the MPI environment (e.g. "mpirun", "srun", etc).

#--- optional variables that can be set for this experiment:

#OIFS_NAMELIST='my-fort.4'               # custom atmospheric model namelist file
#OIFS_EXEC="<cutome<custom-path>/ifsMASTER.DP"  # model exec to be used for this experiment

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• • It is important to change "/path/to/your/config/oifs-config.edit_me.sh" to the actual path for the oifs-config.edit_me.sh, e.g., "$HOME/openifs-48r1.1/oifs-config.edit_me.sh"
  • The default resources requested in run.ecmwf-hpc2020.job are  8 nodes on the ECMWF hpc2020 machine, with a total of 256 MPI tasks and 4 OpenMP threads. This can be changed as required.
  • For information, the LAUNCH command for batch job submission is set to "srun" without any further options, because all required parallel environment settings are provided through the SLURM script headers.

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# run interactively:
cd $OIFS_EXPT/ab2a/2016092500
./oifs-run

Postprocessing with oifs-run

If in the exp-config.h file the OIFS_PPROC variable has been set to true (or if the --pproc command line parameter was used) then the model output in the experiment directory is further processed after completing the model run.

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The postprocessing groups all model output fields and diagnostics into individual GRIB files with ascending forecast time step. Also, a copy of the atmospheric model namelist file fort.4, as well as the ifs.stat and NODE.01_001 log files are moved into the output folder.

This postprocessing is required if the Metview Python script is to be used later to visualise the model output.

Plotting of model output

Here we describe in a brief summary how plots from the model results can be generated. This permits a first-order sanity check whether the model results look sensible.

as well as the ifs.stat and NODE.01_001 log files are moved into the output folder.

This postprocessing is required if the Metview Python script is to be used later to visualise the model output. This is described in the following section. 

Plotting the model output

Here we describe in a brief summary how plots from the model results can be generated. This permits a first-order sanity check whether the model results look sensible.

Please note that this section does not aim to present an in-depth description of how to visualise the model results. There are many possible ways to read the model output (in GRIB format) and present its content in graphical form. Here we provide only an abridged route to generate a limited number of basic longitude-latitude plots. 

For this example we use the Metview graphics package,developed at ECMWF, For this we use the Metview graphics package developed at ECMWF which is used within an example Jupyter Notebook. 

Step 1:  Copy the Metview processing code to your $OIFS_EXPT location:

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Again, download the Metview data package from this site: https://sites.ecmwf.int/openifs/openifs-data/case_studies/48r1/karl/mv.tar.gz

# download the Metview data package and extract in the experiment directory:
cp mv.tar.gz $OIFS_EXPT
tar -xvzf mv.tar.gz
cd mv

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