Articles | Volume 22, issue 1
https://doi.org/10.5194/os-22-531-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/os-22-531-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
11 Feb 2026
Research article |
| 11 Feb 2026
| 11 Feb 2026
Externally-forced and intrinsic variability of the Mediterranean surface and overturning circulations
Damien Héron
CORRESPONDING AUTHOR
Université Grenoble Alpes, CNRS, INRAE, IRD, Grenoble INP, Institut des Géosciences de l’Environnement (IGE), Grenoble, France
Thierry Penduff
Université Grenoble Alpes, CNRS, INRAE, IRD, Grenoble INP, Institut des Géosciences de l’Environnement (IGE), Grenoble, France
Jean-Michel Brankart
Université Grenoble Alpes, CNRS, INRAE, IRD, Grenoble INP, Institut des Géosciences de l’Environnement (IGE), Grenoble, France
Pierre Brasseur
Université Grenoble Alpes, CNRS, INRAE, IRD, Grenoble INP, Institut des Géosciences de l’Environnement (IGE), Grenoble, France
Samuel Somot
Météo-France, CNRS, Univ. Toulouse, CNRM, Toulouse, France
Robin Waldman
Météo-France, CNRS, Univ. Toulouse, CNRM, Toulouse, France
Romain Pennel
Laboratoire de Météorologie Dynamique (LMD)/IPSL, Ecole Polytechnique, Institut Polytechnique de Paris, ENS, Université PSL, Sorbonne Université, CNRS, Palaiseau, France
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Jean-Michel Brankart, Damien Héron, Lisa Weiss, Thierry Penduff, and Pierre Brasseur
EGUsphere, https://doi.org/10.5194/egusphere-2026-3237, https://doi.org/10.5194/egusphere-2026-3237, 2026
This preprint is open for discussion and under review for Ocean Science (OS).
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In this paper, a method is proposed to estimate directly the low-frequency component of the ocean variability from native observations using statistics from a prior long-term ensemble simulation. The approach is illustrated by the reconstruction of the low-frequency variability of the Mediterranean sea level. The resulting ensemble estimate is assessed against independent observations, showing good reliability.
Jean-Michel Brankart, Damien Héron, Lisa Weiss, Thierry Penduff, and Pierre Brasseur
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In this paper, a method is proposed to estimate directly the low-frequency component of the ocean variability from native observations using statistics from a prior long-term ensemble simulation. The approach is illustrated by the reconstruction of the low-frequency variability of the Mediterranean sea level. The resulting ensemble estimate is assessed against independent observations, showing good reliability.
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Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2026-127, https://doi.org/10.5194/essd-2026-127, 2026
Revised manuscript under review for ESSD
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Sofia Darmaraki, Marco Reale, Robin Waldman, and Vasiliki Metheniti
EGUsphere, https://doi.org/10.5194/egusphere-2026-962, https://doi.org/10.5194/egusphere-2026-962, 2026
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Lohenn Fiol, Stephanie Leroux, Pierre Rampal, and Jean-Michel Brankart
EGUsphere, https://doi.org/10.5194/egusphere-2025-6379, https://doi.org/10.5194/egusphere-2025-6379, 2026
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Claudio M. Pierard, Siren Rühs, Laura Gómez-Navarro, Michael Charles Denes, Florian Meirer, Thierry Penduff, and Erik van Sebille
Nonlin. Processes Geophys., 32, 411–438, https://doi.org/10.5194/npg-32-411-2025, https://doi.org/10.5194/npg-32-411-2025, 2025
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Particle-tracking simulations compute how ocean currents transport material. However, initializing these simulations is often ad hoc. Here, we explore how two different strategies (releasing particles over space or over time) compare. Specifically, we compare the variability in particle trajectories to the variability of particles computed in a 50-member ensemble simulation. We find that releasing the particles over 20 weeks gives variability that is most like that in the ensemble.
Loïc Macé, Luc Vandenbulcke, Jean-Michel Brankart, Jean-François Grailet, Pierre Brasseur, and Marilaure Grégoire
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Loïc Macé, Luc Vandenbulcke, Jean-Michel Brankart, Pierre Brasseur, and Marilaure Grégoire
Biogeosciences, 22, 3747–3768, https://doi.org/10.5194/bg-22-3747-2025, https://doi.org/10.5194/bg-22-3747-2025, 2025
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Lara Börger, Michael Schindelegger, Mengnan Zhao, Rui M. Ponte, Anno Löcher, Bernd Uebbing, Jean-Marc Molines, and Thierry Penduff
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We propose a number of priority areas for the international climate research community to address over the coming decade. Advances in these areas will both increase our understanding of past and future Earth system change, including the societal and environmental impacts of this change, and deliver significantly improved scientific support to international climate policy, such as future IPCC assessments and the UNFCCC Global Stocktake.
Sylvain Mailler, Sotirios Mallios, Arineh Cholakian, Vassilis Amiridis, Laurent Menut, and Romain Pennel
Geosci. Model Dev., 17, 5641–5655, https://doi.org/10.5194/gmd-17-5641-2024, https://doi.org/10.5194/gmd-17-5641-2024, 2024
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Geosci. Model Dev., 17, 5431–5457, https://doi.org/10.5194/gmd-17-5431-2024, https://doi.org/10.5194/gmd-17-5431-2024, 2024
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Laurent Menut, Bertrand Bessagnet, Arineh Cholakian, Guillaume Siour, Sylvain Mailler, and Romain Pennel
Geosci. Model Dev., 17, 3645–3665, https://doi.org/10.5194/gmd-17-3645-2024, https://doi.org/10.5194/gmd-17-3645-2024, 2024
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Mikhail Popov, Jean-Michel Brankart, Arthur Capet, Emmanuel Cosme, and Pierre Brasseur
Ocean Sci., 20, 155–180, https://doi.org/10.5194/os-20-155-2024, https://doi.org/10.5194/os-20-155-2024, 2024
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This study contributes to the development of methods to estimate targeted ocean ecosystem indicators, including their uncertainty, in the framework of the Copernicus Marine Service. A simplified approach is introduced to perform a 4D ensemble analysis and forecast, directly targeting selected biogeochemical variables and indicators (phenology, trophic efficiency, downward flux of organic matter). Care is taken to present the methods and discuss the reliability of the solution proposed.
Sylvain Mailler, Romain Pennel, Laurent Menut, and Arineh Cholakian
Geosci. Model Dev., 16, 7509–7526, https://doi.org/10.5194/gmd-16-7509-2023, https://doi.org/10.5194/gmd-16-7509-2023, 2023
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We show that a new advection scheme named PPM + W (piecewise parabolic method + Walcek) offers geoscientific modellers an alternative, high-performance scheme designed for Cartesian-grid advection, with improved performance over the classical PPM scheme. The computational cost of PPM + W is not higher than that of PPM. With improved accuracy and controlled computational cost, this new scheme may find applications in chemistry-transport models, ocean models or atmospheric circulation models.
Laurent Menut, Arineh Cholakian, Guillaume Siour, Rémy Lapere, Romain Pennel, Sylvain Mailler, and Bertrand Bessagnet
Atmos. Chem. Phys., 23, 7281–7296, https://doi.org/10.5194/acp-23-7281-2023, https://doi.org/10.5194/acp-23-7281-2023, 2023
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This study is about the wildfires occurring in France during the summer 2022. We study the forest fires that took place in the Landes during the summer of 2022. We show the direct impact of these fires on the air quality, especially downstream of the smoke plume towards the Paris region. We quantify the impact of these fires on the pollutants peak concentrations and the possible exceedance of thresholds.
Thibault Guinaldo, Aurore Voldoire, Robin Waldman, Stéphane Saux Picart, and Hervé Roquet
Ocean Sci., 19, 629–647, https://doi.org/10.5194/os-19-629-2023, https://doi.org/10.5194/os-19-629-2023, 2023
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In the summer of 2022, France experienced a series of unprecedented heatwaves. This study is the first to examine the response of sea surface temperatures to these events, using spatial operational data and attributing the observed abnormally warm SSTs to atmospheric forcings. The findings of this study underscore the critical need for an efficient and sustainable operational system to monitor alterations that threaten the oceans in the context of climate change.
Sylvain Mailler, Laurent Menut, Arineh Cholakian, and Romain Pennel
Geosci. Model Dev., 16, 1119–1127, https://doi.org/10.5194/gmd-16-1119-2023, https://doi.org/10.5194/gmd-16-1119-2023, 2023
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Large or even
giantparticles of mineral dust exist in the atmosphere but, so far, solving an non-linear equation was needed to calculate the speed at which they fall in the atmosphere. The model we present, AerSett v1.0 (AERosol SETTling version 1.0), provides a new and simple way of calculating their free-fall velocity in the atmosphere, which will be useful to anyone trying to understand and represent adequately the transport of giant dust particles by the wind.
Stephanie Leroux, Jean-Michel Brankart, Aurélie Albert, Laurent Brodeau, Jean-Marc Molines, Quentin Jamet, Julien Le Sommer, Thierry Penduff, and Pierre Brasseur
Ocean Sci., 18, 1619–1644, https://doi.org/10.5194/os-18-1619-2022, https://doi.org/10.5194/os-18-1619-2022, 2022
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The goal of the study is to evaluate the predictability of the ocean circulation
at a kilometric scale, in order to anticipate the requirements of the future operational forecasting systems. For that purpose, ensemble experiments have been performed with a regional model for the Western Mediterranean (at 1/60° horizontal resolution). From these ensemble experiments, we show that it is possible to compute targeted predictability scores, which depend on initial and model uncertainties.
Aurore Voldoire, Romain Roehrig, Hervé Giordani, Robin Waldman, Yunyan Zhang, Shaocheng Xie, and Marie-Nöelle Bouin
Geosci. Model Dev., 15, 3347–3370, https://doi.org/10.5194/gmd-15-3347-2022, https://doi.org/10.5194/gmd-15-3347-2022, 2022
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A single-column version of the global climate model CNRM-CM6-1 has been designed to ease development and validation of the model physics at the air–sea interface in a simplified environment. This model is then used to assess the ability to represent the sea surface temperature diurnal cycle. We conclude that the sea surface temperature diurnal variability is reasonably well represented in CNRM-CM6-1 with a 1 h coupling time step and the upper-ocean model resolution of 1 m.
Douglas Keller Jr., Yonatan Givon, Romain Pennel, Shira Raveh-Rubin, and Philippe Drobinski
Ocean Sci., 18, 483–510, https://doi.org/10.5194/os-18-483-2022, https://doi.org/10.5194/os-18-483-2022, 2022
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The mistral winds are believed to be the primary source of cooling of the Gulf of Lion, leading to deep convection in the region, a process that mixes the ocean column from the seafloor to the sea surface. However, we have found that seasonal atmospheric changes also significantly cool the Gulf of Lion waters to cause deep convection, rather than mistral winds being the sole source, contributing roughly two-thirds of the required cooling, with the mistral winds contributing the final third.
Guillaume Evin, Samuel Somot, and Benoit Hingray
Earth Syst. Dynam., 12, 1543–1569, https://doi.org/10.5194/esd-12-1543-2021, https://doi.org/10.5194/esd-12-1543-2021, 2021
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This research paper proposes an assessment of mean climate change responses and related uncertainties over Europe for mean seasonal temperature and total seasonal precipitation. An advanced statistical approach is applied to a large ensemble of 87 high-resolution EURO-CORDEX projections. For the first time, we provide a comprehensive estimation of the relative contribution of GCMs and RCMs, RCP scenarios, and internal variability to the total variance of a very large ensemble.
Laurent Menut, Bertrand Bessagnet, Régis Briant, Arineh Cholakian, Florian Couvidat, Sylvain Mailler, Romain Pennel, Guillaume Siour, Paolo Tuccella, Solène Turquety, and Myrto Valari
Geosci. Model Dev., 14, 6781–6811, https://doi.org/10.5194/gmd-14-6781-2021, https://doi.org/10.5194/gmd-14-6781-2021, 2021
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The CHIMERE chemistry-transport model is presented in its new version, V2020r1. Many changes are proposed compared to the previous version. These include online modeling, new parameterizations for aerosols, new emissions schemes, a new parameter file format, the subgrid-scale variability of urban concentrations and new transport schemes.
Yonatan Givon, Douglas Keller Jr., Vered Silverman, Romain Pennel, Philippe Drobinski, and Shira Raveh-Rubin
Weather Clim. Dynam., 2, 609–630, https://doi.org/10.5194/wcd-2-609-2021, https://doi.org/10.5194/wcd-2-609-2021, 2021
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Mistral wind is a renowned phenomenon in the Mediterranean, yet its large-scale controlling mechanisms have not been systematically mapped. Here, using a new mistral database for 1981–2016, the upper-tropospheric flow patterns are classified by a self-organizing map algorithm, resulting in 16 distinct patterns related to Rossby wave life cycles. Each pattern has unique surface impact, having implications to understanding mistral predictability, air–sea interaction and their future projections.
Cited articles
Adloff, F., Somot, S., Sevault, F., Jordà, G., Aznar, R., Déqué, M., Herrmann, M., Marcos, M., Dubois, C., Padorno, E., Alvarez-Fanjul, E., and Gomis, D.: Mediterranean Sea response to climate change in an ensemble of twenty first century scenarios, Climate Dynamics, 45, 2775–2802, https://doi.org/10.1007/s00382-015-2507-3, 2015. a
Adloff, F., Jordà, G., Somot, S., Sevault, F., Arsouze, T., Meyssignac, B., Li, L., and Planton, S.: Improving sea level simulation in Mediterranean regional climate models, Climate Dynamics, 51, 1167–1178, https://doi.org/10.1007/s00382-017-3842-3, 2018. a
Balmaseda, M. A., Trenberth, K. E., and Källén, E.: Distinctive climate signals in reanalysis of global ocean heat content, Geophysical Research Letters, 40, 1754–1759, https://doi.org/10.1002/grl.50382, 2013. a
Benincasa, R., Liguori, G., Pinardi, N., and von Storch, H.: Internal and forced ocean variability in the Mediterranean Sea, Ocean Science 20, 1003–1012, https://doi.org/10.5194/os-20-1003-2024, 2024. a, b, c
Bessières, L., Leroux, S., Brankart, J.-M., Molines, J.-M., Moine, M.-P., Bouttier, P.-A., Penduff, T., Terray, L., Barnier, B., and Sérazin, G.: Development of a probabilistic ocean modelling system based on NEMO 3.5: application at eddying resolution, Geoscientific Model Development, 10, 1091–1106, https://doi.org/10.5194/gmd-10-1091-2017, 2017. a, b
Beuvier, J., Béranger, K., Lebeaupin Brossier, C., Somot, S., Sevault, F., Drillet, Y., Bourdallé‐Badie, R., Ferry, N., and Lyard, F.: Spreading of the Western Mediterranean Deep Water after winter 2005: Time scales and deep cyclone transport, Journal of Geophysical Research: Oceans, 117, 2011JC007679, https://doi.org/10.1029/2011JC007679, 2012. a, b, c
Carret, A., Llovel, W., Penduff, T., and Molines, J.: Atmospherically Forced and Chaotic Interannual Variability of Regional Sea Level and Its Components Over 1993–2015, Journal of Geophysical Research: Oceans, 126, e2020JC017123, https://doi.org/10.1029/2020JC017123, 2021. a, b
Civitarese, G., Gačić, M., Batistić, M., Bensi, M., Cardin, V., Dulčić, J., Garić, R., and Menna, M.: The BiOS mechanism: History, theory, implications, Progress in Oceanography, 216, 103056, https://doi.org/10.1016/j.pocean.2023.103056, 2023. a
Colin, J., Déqué, M., Radu, R., and Somot, S.: Sensitivity study of heavy precipitation in Limited Area Model climate simulations: influence of the size of the domain and the use of the spectral nudging technique, Tellus A: Dynamic Meteorology and Oceanography, 62, 591, https://doi.org/10.1111/j.1600-0870.2010.00467.x, 2010. a
Copernicus Marine Service Information (CMEMS): European Seas Gridded L 4 Sea Surface Heights And Derived Variables Reprocessed 1993 Ongoing, E.U. Marine Data Store (MDS) [data set], https://doi.org/10.48670/moi-00141, 2026. a
Demirov, E. and Pinardi, N.: Simulation of the Mediterranean Sea circulation from 1979 to 1993: Part I. The interannual variability, Journal of Marine Systems, 33-34, 23–50, https://doi.org/10.1016/S0924-7963(02)00051-9, 2002. a
Demirov, E. K. and Pinardi, N.: On the relationship between the water mass pathways and eddy variability in the Western Mediterranean Sea, Journal of Geophysical Research: Oceans, 112, 2005JC003174, https://doi.org/10.1029/2005JC003174, 2007. a, b, c
Gačić, M., Borzelli, G. L. E., Civitarese, G., Cardin, V., and Yari, S.: Can internal processes sustain reversals of the ocean upper circulation? The Ionian Sea example, Geophysical Research Letters, 37, 2010GL043216, https://doi.org/10.1029/2010GL043216, 2010. a, b
Gnesotto, M., Pierini, S., Zanchettin, D., Rubinetti, S., and Rubino, A.: Influence of Intrinsic Oceanic Variability Induced by a Steady Flow on the Mediterranean Sea Level Variability, Journal of Marine Science and Engineering, 12, 1356, https://doi.org/10.3390/jmse12081356, 2024. a
Gonzalez, N. M., Waldman, R., Somot, S., Sevault, F., Chanut, J., and Giordani, H.: Disentangling tidal and fine-scale processes at the Strait of Gibraltar and their influence on the Mediterranean region, Climate Dynamics, 63, 277, https://doi.org/10.1007/s00382-025-07741-5, 2025. a
Grégorio, S., Penduff, T., Sérazin, G., Molines, J.-M., Barnier, B., and Hirschi, J.: Intrinsic Variability of the Atlantic Meridional Overturning Circulation at Interannual-to-Multidecadal Time Scales, Journal of Physical Oceanography, 45, 1929–1946, https://doi.org/10.1175/JPO-D-14-0163.1, 2015. a
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 Science 12, 577–599, https://doi.org/10.5194/os-12-577-2016, 2016. a, b, c, d
Hirschi, J. J., Barnier, B., Böning, C., Biastoch, A., Blaker, A. T., Coward, A., Danilov, S., Drijfhout, S., Getzlaff, K., Griffies, S. M., Hasumi, H., Hewitt, H., Iovino, D., Kawasaki, T., Kiss, A. E., Koldunov, N., Marzocchi, A., Mecking, J. V., Moat, B., Molines, J., Myers, P. G., Penduff, T., Roberts, M., Treguier, A., Sein, D. V., Sidorenko, D., Small, J., Spence, P., Thompson, L., Weijer, W., and Xu, X.: The Atlantic Meridional Overturning Circulation in High‐Resolution Models, Journal of Geophysical Research: Oceans, 125, e2019JC015522, https://doi.org/10.1029/2019JC015522, 2020. a
Hogg, A. M., Penduff, T., Close, S. E., Dewar, W. K., Constantinou, N. C., and Martínez‐Moreno, J.: Circumpolar Variations in the Chaotic Nature of Southern Ocean Eddy Dynamics, Journal of Geophysical Research: Oceans, 127, e2022JC018440, https://doi.org/10.1029/2022JC018440, 2022. a
Jamet, Q., Dewar, W. K., Wienders, N., Deremble, B., Close, S., and Penduff, T.: Locally and Remotely Forced Subtropical AMOC Variability: A Matter of Time Scales, Journal of Climate, 33, 5155–5172, https://doi.org/10.1175/JCLI-D-19-0844.1, 2020. a
Leroux, S., Penduff, T., Bessières, L., Molines, J.-M., Brankart, J.-M., Sérazin, G., Barnier, B., and Terray, L.: Intrinsic and Atmospherically Forced Variability of the AMOC: Insights from a Large-Ensemble Ocean Hindcast, Journal of Climate, 31, 1183–1203, https://doi.org/10.1175/jcli-d-17-0168.1, 2018. a, b, c
Lin, L., Von Storch, H., Chen, X., Jiang, W., and Tang, S.: Link between the internal variability and the baroclinic instability in the Bohai and Yellow Sea, Ocean Dynamics, 73, 793–806, https://doi.org/10.1007/s10236-023-01583-7, 2023. a
Liu, F., Mikolajewicz, U., and Six, K. D.: Drivers of the decadal variability of the North Ionian Gyre upper layer circulation during 1910–2010: a regional modelling study, Climate Dynamics, 58, 2065–2077, https://doi.org/10.1007/s00382-021-05714-y, 2022. a, b
Ludwig, W., Dumont, E., Meybeck, M., and Heussner, S.: River discharges of water and nutrients to the Mediterranean and Black Sea: Major drivers for ecosystem changes during past and future decades?, Progress in Oceanography, 80, 199–217, https://doi.org/10.1016/j.pocean.2009.02.001, 2009. a
Madec, G., Bourdallé-Badie, R., Bouttier, P.-A., Bricaud, C., Bruciaferri, D., Calvert, D., Chanut, J., Clementi, E., Coward, A., Delrosso, D., Istituto Nazionale di Geofisica e Vulcanologia (INGV),Sezione Bologna, Bologna, Italia, Ethé, C., Flavoni, S., Graham, T., Harle, J., Iovino, D., Lea, D., Lévy, C., Lovato, T., Martin, N., Masson, S., Mocavero, S., Paul, J., Rousset, C., Storkey, D., Storto, A., and Vancoppenolle, M.: NEMO ocean engine, in: Notes du Pôle de modélisation de l’Institut Pierre-Simon Laplace (IPSL), Zenodo [code], https://doi.org/10.5281/zenodo.3248739, 2017. a
Menna, M., Suarez, N. R., Civitarese, G., Gačić, M., Rubino, A., and Poulain, P.-M.: Decadal variations of circulation in the Central Mediterranean and its interactions with mesoscale gyres, Deep Sea Research Part II: Topical Studies in Oceanography, 164, 14–24, https://doi.org/10.1016/j.dsr2.2019.02.004, 2019. a
Millot, C. and Taupier-Letage, I.: Circulation in the Mediterranean Sea, in: The Mediterranean Sea, edited by: Saliot, A., Springer Berlin Heidelberg, Berlin, Heidelberg, vol. 5K, 29–66, ISBN 978-3-540-25018-0 978-3-540-31492-9, https://doi.org/10.1007/b107143, 2005. a
Millot, C., Taupier-Letage, I., and Benzohra, M.: The Algerian eddies, Earth-Science Reviews, 27, 203–219, https://doi.org/10.1016/0012-8252(90)90003-E, 1990. a
Nabat, P., Somot, S., Cassou, C., Mallet, M., Michou, M., Bouniol, D., Decharme, B., Drugé, T., Roehrig, R., and Saint-Martin, D.: Modulation of radiative aerosols effects by atmospheric circulation over the Euro-Mediterranean region, Atmospheric Chemistry and Physics, 20, 8315–8349, https://doi.org/10.5194/acp-20-8315-2020, 2020. a, b
Nagy, H., Di Lorenzo, E., and El-Gindy, A.: The impact of climate change on circulation patterns in the Eastern Mediterranean Sea upper layer using Med-ROMS model, Progress in Oceanography, 175, 226–244, https://doi.org/10.1016/j.pocean.2019.04.012, 2019. a
Narinc, O., Penduff, T., Maze, G., Leroux, S., and Molines, J.-M.: North Atlantic Subtropical Mode Water properties: intrinsic and atmospherically forced interannual variability, Ocean Science 20, 1351–1365, https://doi.org/10.5194/os-20-1351-2024, 2024. a, b, c
Peliz, A., Boutov, D., and Teles-Machado, A.: The Alboran Sea mesoscale in a long term high resolution simulation: Statistical analysis, Ocean Modelling, 72, 32–52, https://doi.org/10.1016/j.ocemod.2013.07.002, 2013. a
Penduff, T., Barnier, B., Terray, L., Sérazin, G., Gregorio, S., Brankart, J.-M., Moine, M.-P., Molines, J., and Brasseur, P.: Ensembles of eddying ocean simulations for climate. CLIVAR Exchanges, 19, 26–29, https://www.clivar.org/sites/default/files/documents/exchanges65_0.pdf (last access: 6 February 2026), 2014. a
Pinardi, N. and Masetti, E.: Variability of the large scale general circulation of the Mediterranean Sea from observations and modelling: a review, Palaeogeography, Palaeoclimatology, Palaeoecology, 158, 153–173, https://doi.org/10.1016/S0031-0182(00)00048-1, 2000. a, b
Pinardi, N., Zavatarelli, M., Adani, M., Coppini, G., Fratianni, C., Oddo, P., Simoncelli, S., Tonani, M., Lyubartsev, V., Dobricic, S., and Bonaduce, A.: Mediterranean Sea large-scale low-frequency ocean variability and water mass formation rates from 1987 to 2007: A retrospective analysis, Progress in Oceanography, 132, 318–332, https://doi.org/10.1016/j.pocean.2013.11.003, 2015. a
Pinardi, N., Cessi, P., Borile, F., and Wolfe, C. L. P.: The Mediterranean Sea Overturning Circulation, Journal of Physical Oceanography, 49, 1699–1721, https://doi.org/10.1175/JPO-D-18-0254.1, 2019. a
Popov, M., Brankart, J.-M., Molines, J.-M., Leroux, S., Penduff, T., and Brasseur, P.: Development of a probabilistic ocean modelling system based on NEMO4.0: a contribution to the SEAMLESS project (deliverable 3.3), Zenodo [code], https://doi.org/10.5281/zenodo.6303007, 2022. a
Puillat, I., Taupier-Letage, I., and Millot, C.: Algerian Eddies lifetime can near 3 years, Journal of Marine Systems, 31, 245–259, https://doi.org/10.1016/S0924-7963(01)00056-2, 2002. a
Robinson, A., Leslie, W., Theocharis, A., and Lascaratos, A.: Mediterranean Sea Circulation, in: Encyclopedia of Ocean Sciences, 1689–1705, Elsevier, ISBN 978-0-12-227430-5, https://doi.org/10.1006/rwos.2001.0376, 2001. a
Rubino, A., Gačić, M., Bensi, M., Kovačević, V., Malačič, V., Menna, M., Negretti, M. E., Sommeria, J., Zanchettin, D., Barreto, R. V., Ursella, L., Cardin, V., Civitarese, G., Orlić, M., Petelin, B., and Siena, G.: Experimental evidence of long-term oceanic circulation reversals without wind influence in the North Ionian Sea, Scientific Reports, 10, 1905, https://doi.org/10.1038/s41598-020-57862-6, 2020. a
Rubino, A., Pierini, S., Rubinetti, S., Gnesotto, M., and Zanchettin, D.: The Skeleton of the Mediterranean Sea, Journal of Marine Science and Engineering, 11, 2098, https://doi.org/10.3390/jmse11112098, 2023. a
Ruti, P. M., Somot, S., Giorgi, F., Dubois, C., Flaounas, E., Obermann, A., Dell’Aquila, A., Pisacane, G., Harzallah, A., Lombardi, E., Ahrens, B., Akhtar, N., Alias, A., Arsouze, T., Aznar, R., Bastin, S., Bartholy, J., Béranger, K., Beuvier, J., Bouffies-Cloché, S., Brauch, J., Cabos, W., Calmanti, S., Calvet, J.-C., Carillo, A., Conte, D., Coppola, E., Djurdjevic, V., Drobinski, P., Elizalde-Arellano, A., Gaertner, M., Galàn, P., Gallardo, C., Gualdi, S., Goncalves, M., Jorba, O., Jordà, G., L’Heveder, B., Lebeaupin-Brossier, C., Li, L., Liguori, G., Lionello, P., Maciàs, D., Nabat, P., Önol, B., Raikovic, B., Ramage, K., Sevault, F., Sannino, G., Struglia, M. V., Sanna, A., Torma, C., and Vervatis, V.: Med-CORDEX Initiative for Mediterranean Climate Studies, Bulletin of the American Meteorological Society, 97, 1187–1208, https://doi.org/10.1175/BAMS-D-14-00176.1, 2016. a
Sammartino, S., García Lafuente, J., Naranjo, C., Sánchez Garrido, J. C., Sánchez Leal, R., and Sánchez Román, A.: Ten years of marine current measurements in Espartel Sill, Strait of Gibraltar, Journal of Geophysical Research: Oceans, 120, 6309–6328, https://doi.org/10.1002/2014JC010674, 2015. a
Sayol, J.-M., Marcos, M., Garcia-Garcia, D., and Vigo, I.: Seasonal and interannual variability of Mediterranean Sea overturning circulation, Deep Sea Research Part I: Oceanographic Research Papers, 198, 104081, https://doi.org/10.1016/j.dsr.2023.104081, 2023. a, b
Schroeder, K., Garcìa-Lafuente, J., Josey, S. A., Artale, V., Nardelli, B. B., Carrillo, A., Gačić, M., Gasparini, G. P., Herrmann, M., Lionello, P., Ludwig, W., Millot, C., Özsoy, E., Pisacane, G., Sánchez-Garrido, J. C., Sannino, G., Santoleri, R., Somot, S., Struglia, M., Stanev, E., Taupier-Letage, I., Tsimplis, M. N., Vargas-Yáñez, M., Zervakis, V., and Zodiatis, G.: Circulation of the Mediterranean Sea and its Variability, in: The Climate of the Mediterranean Region, Elsevier, 187–256, ISBN 978-0-12-416042-2, https://doi.org/10.1016/B978-0-12-416042-2.00003-3, 2012. a
Soto-Navarro, J., Somot, S., Sevault, F., Beuvier, J., Criado-Aldeanueva, F., García-Lafuente, J., and Béranger, K.: Evaluation of regional ocean circulation models for the Mediterranean Sea at the Strait of Gibraltar: volume transport and thermohaline properties of the outflow, Climate Dynamics, 44, 1277–1292, https://doi.org/10.1007/s00382-014-2179-4, 2015. a
Sérazin, G., Penduff, T., Grégorio, S., Barnier, B., Molines, J.-M., and Terray, L.: Intrinsic Variability of Sea Level from Global Ocean Simulations: Spatiotemporal Scales, Journal of Climate, 28, 4279–4292, https://doi.org/10.1175/JCLI-D-14-00554.1, 2015. a, b
Viúdez, A., Pinot, J., and Haney, R. L.: On the upper layer circulation in the Alboran Sea, Journal of Geophysical Research: Oceans, 103, 21653–21666, https://doi.org/10.1029/98JC01082, 1998. a
Waldman, R., Somot, S., Herrmann, M., Bosse, A., Caniaux, G., Estournel, C., Houpert, L., Prieur, L., Sevault, F., and Testor, P.: Modeling the intense 2012–2013 dense water formation event in the northwestern Mediterranean Sea: Evaluation with an ensemble simulation approach: MODELING THE 2012–2013 DWF EVENT, Journal of Geophysical Research: Oceans, 122, 1297–1324, https://doi.org/10.1002/2016JC012437, 2017. a, b, c, d
Wolfe, C. L., Cessi, P., and Cornuelle, B. D.: An Intrinsic Mode of Interannual Variability in the Indian Ocean, Journal of Physical Oceanography, 47, 701–719, https://doi.org/10.1175/JPO-D-16-0177.1, 2017. a
Short summary
Our study used realistic ocean simulations to determine how much of the Mediterranean’s circulation is due to natural randomness rather than atmospheric forcing. We found that spontaneous ocean variability is strong in several regions and can persist for years or even decades. This randomness influences how well models and observations can capture the Mediterranean’s response to climate change.
Our study used realistic ocean simulations to determine how much of the Mediterranean’s...
