= GYRE_PISCES

Last edition: '''[[Wikinfo(changed_ts)]]''' by '''[[Wikinfo(changed_by)]]'''

Idealized configuration representing double gyres in the North hemisphere, Beta-plane with a regular grid spacing at 1° horizontal resolution (and possible use as a benchmark by easily inscreasing grid size), 101 vertical levels, forced with analytical heat, freshwater and wind-stress fields.[[BR]]
This configuration is coupled to [http://www.geosci-model-dev.net/8/2465/2015/ PISCES] biogeochemichal model.

== Running GYRE as a benchmark

This simple configuration can be used as a benchmark since it is easy to increase resolution (and in this case no physical meaning of outputs):

1. Choose the grid size

   In `CONFIG/GYRE/EXP00`, edit your `namelist_cfg` file to change the `jp_cfg`, `jpi`, `jpj`, `jpk` variables in &namcfg:
   ||  `jp_cfg`  ||  `jpi`  ||  `jpj`  ||  `jpk`   ||  Number of points  ||  Equivalent to  ||
   ||           1||       30||       20||   101    ||               60600||GYRE 1°          ||
   ||          25||      750||      500||   101    ||            37875000||ORCA 1/2°        ||
   ||          50||     1500||     1000||   101    ||           151500000||ORCA 1/4°        ||
   ||         150||     4500||     3000||   101    ||          1363500000||ORCA 1/12°       ||
   ||         200||     6000||     4000||   101    ||          2424000000||ORCA 1/16°       ||

2. In `namelist_cfg` again, avoid problems in the physics (and results will not be meaningful in terms of physics) by setting `nn_bench = 1` in &namctl
{{{#!f
   nn_bench    =    1     !  Bench mode (1/0): CAUTION use zero except for bench
}}}

3. If you increase domain size, you may need to decrease time-step (for stability) by changing `rn_rdt` value in &namdom (i.e. for `jp_cfg = 150`, ORCA12 equivalent, use `rn_rdt = 1200`)
{{{#!f
   rn_rdt      = 1200.     !  time step for the dynamics
}}}

4. Optional, in order to increase the number of MPI communication for benchmark purposes: you can change the number of sub-timesteps computed in the time-splitting scheme each iteration. First change the list of active CPP keys for your experiment, in `CONFIG/"your configuration name"/cpp_"your configuration name".fcm` : replace key_dynspg_flt by key_dynspg_ts and recompile/create your executable again
{{{#!sh
   makenemo [...] add_key 'key_dynspg_ts' del_key 'key_dynspg_flt'
}}}
In your `namelist_cfg` file, edit the &namsplit namelist by adding the following line: 
{{{#!f
   nn_baro       =    30               !  Number of iterations of barotropic mode/
}}}
`nn_baro = 30` is a kind of minimum (we usually use 30 to 60).So than increasing the `nn_baro` value will increase the number of MPI communications.

The GYRE CPP keys, namelists and scripts can be explored in the `GYRE` configuration directory (`NEMOGCM/CONFIG/GYRE` and `NEMOGCM/CONFIG/GYRE/EXP00`).

Find [http://prodn.idris.fr/thredds/catalog/ipsl_public/reee451/NEMO_OUT/GYRE/catalog.html here] monthly mean outputs of 1 year run