The NEMO configurations

Person in charge: Christian Ethé

1. Description

The NEMO configuration described here is an ocean-sea ice configuration based on the version 3.6 stable of NEMO (Nucleus for European Models of the Ocean), which includes three major components: the ocean physics NEMO-OPA, the sea-ice dynamics and thermodynamics NEMO-LIM3 and the ocean biogeochemistry NEMO-PISCES. The available resolutions builded on the ORCA quasi-isotropic global tripolar grid are 2°, 1° and 1/4°. The 1° (eORCA1) and 1/4° (eORCA025) are extended to the south so as to better represent the contribution of Antarctic under-ice shelf seas to the Southern ocean freshwater cycle. Notice that the biogeochemical model PISCES can be run coupled online with the dynamics ( ORCA1-LIM3-PISCES for example ) or in a "stand-alone" ( ORCA2-LIM3-PISCES). This NEMO configuration has been builded to be able to perfom the OMIP6 experiments ( omip1 and omip2 protocol) ; thus some specific sources code are available through the shaconemo repository.

To find out more about the model description and the reference configurations, go here: To use and extract NEMO, you first need to register and choose a login/passwd

2. Technical details

2.1. The configuration on mod.def

#-H- NEMO_v6.1  NEMOGCM for CMIP6 exercise
#-H- NEMO_v6.1  libIGCM trunk rev 1534
#-H- NEMO_v6.1  XIOS branch xios-2.5 rev 1903
#-M- NEMO_v6.1
#-C- NEMO_v6.1  trunk/libIGCM                                                               1548  10 libIGCM         .
#-C- NEMO_v6.1  branches/2015/nemo_v3_6_STABLE/NEMOGCM                                      9455   7  .              modeles
#-C- NEMO_v6.1  trunk/ORCA1_LIM3_PISCES                                                      275  17  .              modeles/NEMOGCM/CONFIG
#-C- NEMO_v6.1  trunk/eORCA025_LIM3                                                          275  17  .              modeles/NEMOGCM/CONFIG
#-C- NEMO_v6.1  trunk/eORCA025_LIM3_PISCES                                                   275  17  .              modeles/NEMOGCM/CONFIG
#-C- NEMO_v6.1  trunk/ORCA1_OFF_PISCES                                                       275  17  .              modeles/NEMOGCM/CONFIG
#-C- NEMO_v6.1  CONFIG/UNIFORM/v6/NEMO_v6                                                   6072   8  NEMO_v6        config
#-C- NEMO_v6.1  XIOS/branchs/xios-2.5                                                       1903  12  XIOS           modeles


2.2. Setting up pre-builded NEMO configurations

2.2.1. Installation and Compiling

svn co modipsl
cd modipsl/util

./model NEMO_v6.1

Several built-in configurations are provided to evaluate the skills and performances of the model ( cd ../config/NEMO_v6 ). They can be used as first easy set-up and as template for setting up a new configuration :

  • ORCA2_LIM3_PISCES : the fully coupled global ocean on 2° horizontal grid and 31 vertical levels, with 10 levels in the top 100m


  • ORCA2_OFF_PISCES : stand-alone PISCES biogeochemical model on ORCA2 - dynamical fields are pre-calculated and read with specific time frequency


  • ORCA1_LIM3_PISCES : the fully coupled global ocean on 1° horizontal grid, extended to the south and 75 vertical levels ( from 1~m at the surface to 10~m at 100~m depth, and reaches 200~m at the bottom)


  • ORCA1_LIM3_PISCES_CMIP6 : the ORCA1_LIM3_PISCES but to run the OMIP6 experiments


  • ORCA1_OFF_PISCES : stand-alone PISCES biogeochemical model on ORCA1


  • ORCA025_LIM3 : the global ocean on 1/4° horizontal grid, without the PISCES model

gmake ORCA025LIM3

  • ORCA025_LIM3_PISCES : the fully coupled global ocean on 1/4° horizontal grid


2.2.2. Creating the job

For example : To perform an interannual COREII atmospheric forcing using the built eORCA1_LIM3_PISCES

cd modipsl/config/NEMO_v6
cp EXPERIMENTS/ORCA1_LIM3_PISCES/ia/config.card .


2.3. Running the model

2.3.1. Input files: atmospheric forcings, initial states, namelists

The card files ( opa9.card for orca1_lim and pisces.card for pisces) contain the list of files needed to perform the simulation.
These files are described here:

2.3.2. The run

This example is a 62 years CORE2 forcing interannual run of ORCA1_LIM3_PISCES split in 1-year jobs.

#----- Short Name of Experiment
LongName="ORCA1_LIM3_PISCES NEMO configuration"
#D- Choice of experiment in EXPERIEMENTS directory
#-- leap, noleap, 360d
#-- Begin and end of Job
#-- "YYYY-MM-DD"
#-- 1Y, 1M, 5D, 1D

2.3.3. Submit the job

on jean-zay :  sbatch Job_eOR1L3P-IA-CORE
on irene :  ccc_msub Job_eOR1L3P-IA-CORE

2.4. Performances

The performances of the NEMO configuration can be find here:

Last modified 4 months ago Last modified on 05/25/22 11:00:45