November 2016
Updated  November 2017
Updated  March 2019 at UCL

François Massonnet
francois.massonnet@uclouvain.be/bsc.es

Everything available to set up the Ensemble Kalman filter (EnKF) for NEMO and EC-Earth


#### **!!! ALL COMPILATIONS AND CREATION OF BINARY FILES SHOULD BE DONE ON THE HPC !!!**
#### 

1. **Go to the HPC**

2. **Clone the git repository** (some HPCs don't allow communication with the web, in this case clone locally and rsync the git project to HPC)

```
git clone https://gogs.elic.ucl.ac.be/fmasson/EnKF.git
```

3. **Compile the EnKF code**

The folder EnKF-MPI-TOPAZ is a modified copy of the source code found at NERSC (http://enkf.nersc.no/Code/NERSC_implementation/V2/)

It has been modified as to work with NEMO and LIM, by F. Massonnet and C. König Beatty. The code itself should not be modified, unless there are good reasons to do so.

```
cd EnKF-MPI-TOPAZ
make clean
configure_ecearth
make 
```

An executable EnKF should be produced. Try to run it to see if you get the following information message:

   bsc32526@login2:/gpfs/projects/bsc32/bsc32526/enkf/EnKF-assimilation/EnKF-MPI-TOPAZ> ./EnKF
   Inne i start_mpi: qmpi_proc_num =           0  master = T
   MPI started with 1 processors
   Usage: EnKF <parameter file>
          EnKF -h
   Options:
     -h -- describe parameter fie format

B/ Compilation of the program to convert NetCDF files to binaries
-----------------------------------------------------------------
>> cd ../conversion_uf/
>> make clean
>> source ../enkf_modules_to_load.txt
>> make

Two executables named prep_obs_ORCA1 and prep_obs_ORCA25 should be created. Try them:
>> ./prep_obs_ORCA1
           0
 
  (prep_obs) takes a real obs, extracts the desired variable and outputs
  it in a format that the EnKF can read & treat ('observations.uf').
 
  A file named mask.nc containing the variables tmaskutil, nav_lon and nav_lat
  is expected to be in the current directory (ORCA-file)
 
  Three command line arguments are expected:
  1. Path to the nc file of which the data is to be extracted.
  2. Variable name that can be found in there, 'h_i_htc1' or
     'at_i'. or dxdy_ice
  3. A tag with the date, e.g. 19790520
 
  Hope to see you again soon.
 
(prep_obs): Stopped.

C/ Compilation of the program to post-process the restarts after assimilation ("sanity_check")
----------------------------------------------------------------------------------------------
The folder sanity_check is a set of routines that make sure that the restarts provided by the EnKF can be read by NEMO. These are home-made (François Massonnet, see also description in http://www.sciencedirect.com/science/article/pii/S1463500315000050


>> cd ../sanity_check/
>> make clean
>> source ../enkf_modules_to_load.txt
>> make

An executable named sanity_checked is created, try it:
>> ./sanity_check
 
  sanity_check_LIM3 needs arguments: 
  -analysis_file_ice 
  -forecast_file_ice 
  -analysis_file_oce 
  -forecast_file_oce 
  Checks NEMO-LIM3 ice and ocean analyses restarst (netcdf) file for sanity and 
 fixesthem if necessary.
 
  Sanity means for now:
  Strongly follow limupdate.F90
  Files mask.nc and mesh_hgr.nc need to be in the current directory
 
  Hope to see you again soon.
 
  Chris König Beatty 
  Francois Massonnet -- francois.massonnet@uclouvain.be
  Last update: 2013
  Last update: 2016 (to work with NEMO3.6)
(sanity_check): Stopped.



D/ Convert NetCDF observations (already interpolated on the ORCA grids) to UF format:
-------------------------------------------------------------------------------------
>> cd ../conversion_uf/

open convert.bash, check it, and run it (always on HPC)