Last update: February 2020

 Quick description

The numerical model ALADIN (Aire Limitée Adaptation dynamique Développement InterNational) is a limited area bi-spectral model.
Since the beginning of the years 2000s, the ALADIN model is used at CNRM as a Regional Climate Model (RCM) with the name CNRM-ALADIN (or ALADIN-Climat). In the climate model family of CNRM, ALADIN can be seen as the limited area version of the ARPEGE-Climate model with which it shares most of the dynamics and physics or as the hydrostatique version of AROME.

The main advantage of RCMs is to limit the numerical cost of simulations with respect to global climate model at the same resolution. Therefore they allow to explore the climate representation at very fine scale.

At CNRM, we are currently developing and using the version 6 of CNRM-ALADIN that is based on cycle 37t1 of ARPEGE-IFS and on the version 6 of the CNRM climate physics that is common to ARPEGE-Climat, CNRM-CM6 or CNRM-ESM2, model for example used in CMIP6. In its simplest version, CNRM-ALADIN represent the atmosphere component of the climate as well as the land surface and its interactions with the atmosphere thanks to the SURFEX model.

 Main uses

In climate mode, CNRM-ALADIN can be used in different configurations:

  • Contribution of CNRM to the international programme WCRP CORDEX (lien) in particular over the Mediterranean and European domains (Med-CORDEX, Euro-CORDEX).
  • Contribution to the version 2020 of the web portal of the French national climate service (DRIAS) and to the European climate service (Climate Data Store of C3S)
  • Dedicated simulations for geographical areas of interest: metropolitan France (Colin et al. 2010, Daniel et al. 2019), South-East Atlantic Ocean (Mallet et al. 2019), La Réunion, Guadeloupe (Cantet et al. 2014), Martinique, Nouvelle Calédonie, Polynésie Française (Hopuare et al. 2015), North America (Lucas-Picher et al. 2013, 2015).
  • Simulations at very low resolution (125 or 150 km, Herrmann et al. 2011)
  • Simulations at very high résolution (12 km, Déqué and Somot 2008, Colin et al. 2010, Herrmann et al. 2011, Bador et al. 2017).
  • Frequent use of the spectral nudging option (Radu et al. 2008, Colin et al. 2010, Herrmann et al. 2011)
  • Use in forced mode by sea surface temperature and sea ice coverage (Herrmann et al. 2011, Bador et al. 2017)
  • Use in coupled mode with interactive aerosol scheme (ALADIN-TACTIC, Nabat et al. 2015b, Mallet et al. 2019, Drugé et al. 2019) or in a fully-coupled regional climate system model CNRM-RCSM including the representation of surface hydrology and of the regional ocean (Sevault et al. 2014, Nabat et al. 2014, Somot et al. 2018).
  • Use in academic mode (Big-Brother/Little-Brother) in which CNRM-ALADIN is driven by CNRM-ARPEGE at the same resolution and with the same physics (Colin et al. 2010)
  • Use in perfect boundary condition mode in which the lateral and surface boundary forcings come from global reanalyses (Nabat et al. 2014, Sanchez-Gomez and Somot 2018, Daniel et al. 2019).
  • Use in scenario mode in which the lateral and surface boundary conditions come from global climate models (CNRM-CM5, CNRM-ESM2 ou de GCMs issus de CMIP) to perform historical and scenario simulations (Sanchez-Gomez et al. 2009b, Déqué et al. 2012, Tramblay et al. 2013, Bador et al. 2017, Boé et al. 2020, Gutiérrez et al. 2020).

 Scientific applications using CNRM-ALADIN in climate mode

The scientific studies carried out with ALADIN-Climate at CNRM cover:

  • Study of the strengths and limits of the regional climate models: academic study in Big-Brother/Little-Brother experiments (Radu et al. 2008, Colin et al. 2010), sensitivity study to the domain size (Colin et al. 2010, Herrmann et al. 2011), sensitility study to the model physics (Fardà et al. 2010), sensitivity study to the use of spectral nudging (Radu et al. 2008, Colin et al. 2010, Herrmann et al. 2011), study of the RCM internal variability (Sanchez-Gomez and Somot, 2018), added-value study with respect to the driving model (Déqué and Somot 2008, Herrmann et al. 2011, Ruti et al. 2016), large-scale reproductibility study (Sanchez-Gomez et al. 2009a)
  • The evaluation and sometimes improvement of the model for the representation of the mean climate state (Sevault et al. 2014, Nabat et al. 2015a, Daniel et al. 2019), the heavy precipitation events (Déqué and Somot 2008, Colin et al. 2010, Fumière et al. 2019), the regional winds over sea (Herrmann et al. 2011), the intense air-sea fluxes (Waldman et al. 2017a), the urban heat island over Paris (Daniel et al. 2019), the floods (Lucas-Picher et al. 2015), the heat waves (Lemonsu et al. 2014, Bador et al. 2017), the Mediterranean Sea water and heat budgets (Sanchez-Gomez et al. 2011), the Mediterranean cyclogenesis (Sanchez-Gomez and Somot 2018), the weather regimes (Sanchez-Gomez et al. 2009a).
  • the study and the attribution of past trends (Nabat et al. 2014, Drugé et al. 2019)
  • The study of the regional climate change and the related uncertainties using dynamical downscaling (regionalization) of global scenarios: Sanchez-Gomez et al. 2009, Déqué and Somot 2010, Driouech et al. 2010, Déqué et al. 2012, Jacob et al. 2013
  • the characterization of the future climate evolution during the 21st century at the regional scales and of the associated uncertainties (Sanchez-Gomez et al. 2009, Déqué and Somot 2010, Driouech et al. 2010, Déqué et al. 2012, Jacob et al. 2013, Tramblay et al. 2013, Gutiérrez et al. 2020, Boé et al. 2020)
  • the study of the regional impacts of climate change on the water resources (Tramblay et al. 2013), on the photovoltaic energy production (Gutiérrez et al. 2020).

 Where can I find outputs of ALADIN-Climat ?

The outputs (netcdf format) of the CNRM-ALADIN climate model can be found on :

  • the ESGF (Earth System Grid Federation) for example the CNRM ESGF datanode or the ESGF IPSL datanode. Se also the web page CORDEX ESGF.
  • the Med-CORDEX database (
  • on request to
  • on the Climate Data Store of the European climate service C3S (ici)
  • (for the historians,) the dedicated databases of the European projects ENSEMBLES (data) and CECILIA (data)

 Some illustrations and movies using CNRM-ALADIN model outputs

  • Movie of a tropical cyclone track close to La Réunion island (South-West Indian Ocean) at a resolution of 150km by the global climate model CNRM-ESM2-1 (left) and at a resolution of 12km y the regional climate model CNRM-ALADIN63 (right). Big thank to M-D. Leroux and D. Salas for this movie. here

 History of CNRM-ALADIN

  • Historically, ALADIN development started at the beginning of the 1990s within a broad consortium gathering numerous weather centres in Europe. In its "operational numerical weather forecast" version, it is presented on the following web pages: First link Second link Third link
    The very first reference articles presenting ALADIN are Bubnova et al. 1995 (Monthly Weather Review, n.123) and Radnoti 1995 (Mon. Wea. Rev., n.123).
  • Since the beginning of the years 2000s, the ALADIN model is used at CNRM as a Regional Climate Model (RCM) with the name CNRM-ALADIN (or ALADIN-Climat). The first climate version of ALADIN is based on the cycle 24t1 of ARPEGE-ALADIN and on the version 4 of the climate physics (physics of the ARPEGE-Climat model version 4). This model (called at that time ALADIN-Climat v4) allowed to participate to the European projects ENSEMBLES and CECLIA, to the national project SCAMPEI, to the French national portal DRIAS and to publish the first scientific articles using ALADIN-Climate (Spiridonov et al. 2005, Déqué and Somot 2008, Radu et al. 2008, Sanchez-Gomez et al. 2009a, 2009b, 2011, Fardà et al. 2010).
  • The version 5 of CNRM-ALADIN (also called ALADIN-Climat v5) is based on the cycle 32t0 of ARPEGE-ALADIN and on the version 5 of the CNRM climate. This climate physics is also used in CMIP5 with ARPEGE-Climate and CNRM-CM5. CNRM-ALADIN5 has been widely used in the first phase of the international CORDEX initiative for the domains Mediterranean (Med-CORDEX, version 5.2, CNRM-ALADIN52, Tramblay et al. 2013, Jacob et al. 2013, Nabat et al. 2014a, 2014b, Sevault et al. 2014), Europe (Euro-CORDEX, version 5.3, CNRM-ALADIN53, Bador et al. 2017), Africa (CORDEX Africa, CNRM-ALADIN52) and North America (CORDEX North-America, Lucas-Picher et al. 2013). We also use it in the European projects CLIM-RUN and IMPACT2C as well as in the national projects ANR MEDUP and ANR REMEMBER. Finally, CNRM-ALADIN5 served to feed the version 2014 of the web portal of the French national climate servce DRIAS with dedicated simulations over France including the French outermost territories.

 Other users of ALADIN in climate mode

In climate mode, the model ALADIN is or has been used by other research laboratories of the ALADIN consortium and more particularly by the weather services of Bulgaria (big thank to V. Spiridonov for guiding our first steps), Czech Republic (A. Fardà, P. Skalak), Hungary, Romania (R. Radu) and Morocco (F. Driouech). The regional climate model ALADIN has also been used at OURANOS OURANOS (Canada, D. Caya, D. Paquin) and CERFACS (France, M. Bador). Finally, ALADIN is currently used by institutes from the ALADIN-HIRLAM consortium ALADIN-HIRLAM under the name HCLIM-ALADIN (SMHI).

 Some key reference publications for CNRM-ALADIN

Intercomparaison study of CNRM-ALADIN with the other European RCMs:

Vautard et al. (in rev.)
Coppola et al. (in rev.)

CNRM-ALADIN version 6:

Nabat, P., Somot, S., Cassou, C., Mallet, M., Michou, M., Bouniol, D., Decharme, B., Drugé, T., Roehrig, R., and Saint-Martin, D. (2020) Modulation of radiative aerosols effects by atmospheric circulation over the Euro-Mediterranean region, Atmos. Chem. Phys., 20, 8315–8349,

Daniel, M., Lemonsu, A., Déqué, M., Somot, S., Alias, A., & Masson, V. (2019). Benefits of explicit urban parameterization in regional climate modeling to study climate and city interactions. Climate dynamics, 52(5-6), 2745-2764.

CNRM-ALADIN or ALADIN-Climate version 5:

Herrmann M., Somot S., Calmanti S., Dubois C., Sevault F. (2011) “Representation of daily wind speed spatial and temporal variability and intense wind events over the Mediterranean Sea using dynamical downscaling : impact of the regional climate model configuration”, Nat. Hazards Earth Syst. Sci., 11, 1983-2001, doi:10.5194/nhess-11-1983-2011

Colin J., Déqué M., Radu R., Somot S. (2010) Sensitivity study of heavy precipitations in Limited Area Model climate simulation: influence of the size of the domain and the use of the spectral nudging technique. Tellus-A, 62(5), 591-604. DOI: 10.1111/j.1600-0870.2010.00467.x

CNRM-ALADIN or ALADIN-Climat version 4:

Radu, R., Déqué, M., Somot, S. (2008) Spectral nudging in a spectral regional climate model. Tellus. 60A(5):885-897. doi: 10.1111/j.1600-0870.2008.00343.x

The first published reference for ALADIN-Climate:

Spiridonov V., Somot S., Déqué M. (2005) : ALADIN-Climate : from the origins to present date. ALADIN Newsletter n. 29 (nov. 2005)

The first talk presenting ALADIN-Climat:

Somot S., Spiridonov V., Marquet P., Déqué M. (2004) : Climate version of the LAM ALADIN : First validation of a 10-year simulation over Europe. Regional Climate Model Workshop, Prague (Rép. Tchèque) 29 novembre - 3 décembre 2004