NEMOMED12 is a regional version on the Mediterranean Sea of the NEMO-V3.6 Model (Madec et al., 2016). The model grid is an extraction of the global one ORCA 1/12°. A description of the bathymetry is given in the technical documentation.
The characteristics can be summarized as follows:

- the resolution of the grid to the 1/12° varies approximately from 7.5 km in the south to 6 km in the north of the domain; this resolution corresponds approximately to the first radius of deformation and makes the model eddy-permitting and not eddy-resolving like PAM or MED16;

- 75 vertical Z-levels with an inhomogenous distribution from 1 m at the surface to 134 m at the bottom and with 25 levels in the first 150 meters; the maximum depth is 4400 m in the South-East of Rhodes (cf fig. 1).

Fig. 1

- a buffer zone is placed in the Atlantic west the Straits of Gibraltar in order to allow the balance of salt and heat of the Mediterranean; one carries out there a relaxation in temperature and salinity from the surface to the bottom towards a reanalysis or the output of a global model; this relaxation is very strong at the most distant point from Gibraltar (3 days) then decreases when approaching it (100 days)

- at the surface, a time-filtered free surface equation is resolved; the time-step is 12 minutes;

- lateral physics configuration: biharmonic viscosity, harmonic isoneutral tracer diffusivity, partial free slip lateral boundary condition on momentum;

- vertical physics configuration: Ecume bulk parametrization of surface turbulent fluxes, TKE turbulence scheme, EVD convection scheme, nonlinear bottom friction;

- the model can be used in forced configuration by fluxes resulting from atmospheric simulations, or coupled with the ALADIN-Climate regional model (CNRM-RCSM6 coupled model); besides the ISBA-CTRIP hydrologic modelling system can be used;

- the Black Sea is not included in the grid of the model, it is treated as a river because of its very low salinity; moreover, when the CTRIP model is not present, we use the monthly climatological or interannual runoff of the main rivers of the Mediterranean Sea catchment basin, which makes it possible not to use any salinity relaxation, provided the atmospheric water flux is good enough.


The NEMOMED12 model allows to represent the Mediterranean thermohaline circulation, forced by the surface buoyancy (water and heat) loss and characterized by the two-way flow at the Gibraltar Straits and the dense water formation phenomenon. From there, the fields of study which we explore are as follows:

- study of the Mediterranean Sea interannual variability and tendencies, with comparison to the observations when the model is forced by the statistical downscaling by ALADIN-Climate of the ERA-Interim reanalysis fluxes from the NCEP;

- simulation of the impact of climate change: we compute various simulations of the 21st century following scenarios from the GICC

- comparison between forced and coupled simulations: impact of an interactive Mediterranean on the climate and/or impact of an interactive atmosphere on the Mediterranean Sea

- use of the fields resulting from NEMOMED12 simulations to force a coastal ocean model (SYMPHONIE) at its boundaries; it is also used for biogeochemistry models (Eco3-M or PISCES for example).


The main discussions are led at the CNRM among the users of the NEMO model in all its configurations. Besides LOCEAN and ENSTA labs and Mercator-Ocean are usually consulted, as well as the Laboratoire d’Aérologie (Observatoire Midi-Pyrénées).


When using NEMOMED12 the main citations are Beuvier et al., 2012, Hamon et al., 2016, for the beginning with NEMOv3.2, and Waldman et al., 2018, for the NEMOv3.6 update. (see below)

 Publications and technical reports associated to the model

Darmaraki, S., Somot, S., Sevault, F., Nabat, P. (2019). Past variability of Mediterranean Sea marine heatwaves. Geophysical Research Letters, 46.

Dunić, N., Vilibić, I., Šepić, J., Mihanović, H., Sevault, F., Somot, S., Waldman, R., Nabat, P., Arsouze, T., Pennel, R., Jordà, G., and Precali, R. (2019), Performance of multi-decadal ocean simulations in the Adriatic Sea, Ocean Modelling, 134, 84-109, DOI:10.1016/j.ocemod.2019.01.006.

Harzallah, A., Jordà, G., Dubois, C., Sannino, G., Carillo, A., Li, L., Arsouze, T., Cavicchia, L., Beuvier, J., Akhtar, N. (2018): Clim Dyn (2018) 51: 1145.

Waldman R., Brüggemann N., Bosse A., Spall M., Somot S., Sevault F. (2018) Overturning the Mediterranean Thermohaline Circulation. GRL, DOI : 10.1029/2018GL078502 PDF Supplementary

Voldoire A., Decharme B., Pianezze J., Lebeaupin-Brossier C., Sevault F., Seyfried L., Garnier V., Bielli S., Valcke S., Alias A., Accensi M., Ardhuin F., Bouin M.N., Ducrocq V., Faroux S., Giordani H., Léger F., Marsaleix P., Rainaud R., Redelsberger J.-L., Richard E., Riette S. (2017) SURFEX v8.0 interface with OASIS3-MCT to couple atmosphere with hydrology, ocean, waves and sea-ice models, from coastal to global scales. Geosci. Model Dev., 10, 4207–4227, 2017,

Waldman R., Herrmann M., Somot S., Arsouze T., Benshila R., Bosse A., Chanut J., Giordani H., Sevault F., Testor P. (2017b) Impact of the Mesoscale Dynamics on Ocean Deep Convection : The 2012-2013 Case Study in the Northwestern Mediterranean Sea. JGR-Oceans, Special Issue HyMeX-Mermex, sept 2017, doi : 10.1002/2016jc012587 PDF

Waldman R., Somot S., Herrmann M., Bosse A., Caniaux G., Estournel C., Houpert L., Prieur L., Sevault F., Testor P. (2017a) Modelling of the intense 2012-2013 dense water formation event in the northwestern Mediterranean Sea : Evaluation with an ensemble simulation approach. J. Geophys. Res. Oceans, 122, doi:10.1002/2016JC012437, Special Issue HyMeX-Mermex PDF

Hamon, M., Beuvier, J., Somot, S., Lellouche, J.-M., Greiner, E., Jordà, G., Bouin, M.-N., Arsouze, T., Béranger, K., Sevault, F., Dubois, C., Drevillon, M., and Drillet, Y.: Design and validation of MEDRYS, a Mediterranean Sea reanalysis over the period 1992–2013, Ocean Sci., 12, 577–599,, 2016.

Beuvier, J., Béranger K., Lebeaupin-Brossier, C., Somot, S., Sevault, F., Drillet, Y., Bourdalle-Badie, R., Ferry, N., and Lyard, F.: Spreading of the Western Mediterranean Deep Water after winter 2005: time scales and deep cyclone transport, J. Geophys. Res. Oceans, 117, C07022, doi:10.1029/2011JC007679, 2012a.

Lebeaupin Brossier C., Béranger K., Drobinski P. (2012) Sensitivity of the North-western Mediterranean coastal and thermohaline circulations as simulated by the 1/12e resolution oceanic model NEMO-MED12 to the space-time resolution of the atmospheric forcing, Ocean Modelling, 43-44, 94-107.


Madec G., and the NEMO Team, January 2016 : NEMO ocean engine - version3.6 stable -. Note du Pôle de modélisation de l’IPSL n°27.

Arsouze T., Beuvier J., Béranger K., Bourdallé-Badie R., Deltel C., Drillet Y., Drobinski P., Ferry N., Lebeaupin-Brossier C., Lyard F., Sevault F., Somot S. : Release note of the high-resolution oceanic model in the Mediteranean Sea NEMO-MED12 based on NEMO v3.2 version.