EGU General Assembly 2021
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

A NEMO-based model of Sargassum distribution in the Tropical Atlantic 

Rachid Benshila1, Julien Jouanno1, Léo Berline2, Antonin Soulié1, Marie-Hélène Marie-Hélène1, Guillaume Morvan1, Frédéric Diaz2, Julio Sheinbaum3, Cristele Chevalier2, Thierry Thibaut2, Thomas Changeux2, Frédéric Menard2, Sarah Berthet4, Olivier Aumont5, Christian Ethé5, Pierre Nabat4, and Marc Mallet4
Rachid Benshila et al.
  • 1LEGOS, Université de Toulouse, IRD, CNRS, CNES, UPS, Toulouse, France
  • 2Aix-Marseille University, Université de Toulon, CNRS/INSU, IRD, MIO UM 110, Mediterranean Institute of Oceanography (MIO), Campus of Luminy, 13288 Marseille, France
  • 3CICESE, Ensenada, Mexico
  • 4CNRM, Université de Toulouse, Météo-France, CNRS, Toulouse, France
  • 5Laboratoire d’Océanographie et de Climatologie: Expérimentation et Approches Numériques, IRD-IPSL, 4 Place Jussieu, 75005 Paris, France

The Tropical Atlantic is facing a massive proliferation of Sargassum since 2011, with severe environmental and socioeconomic impacts. The development of Sargassum modelling is essential to clarify the link between Sargassum distribution and environmental conditions, and to lay the groundwork for a seasonal forecast on the scale of the Tropical Atlantic basin. We present here a modelling framework based on the NEMO ocean model which integrates transport by currents and waves, stranding at the coast, and physiology of Sargassum with varying internal nutrients quota. The model is initialized from basin scale satellite observations and performance was assessed over the Sargassum year 2017. Model parameters are calibrated through the analysis of large ensembles of simulations, and the sensitivity to forcing fields like riverine nutrients inputs, atmospheric deposition, and waves is investigated. Overall, results demonstrate the ability of the model to reproduce the seasonal cycle and large-scale distribution of Sargassum biomass.

How to cite: Benshila, R., Jouanno, J., Berline, L., Soulié, A., Marie-Hélène, M.-H., Morvan, G., Diaz, F., Sheinbaum, J., Chevalier, C., Thibaut, T., Changeux, T., Menard, F., Berthet, S., Aumont, O., Ethé, C., Nabat, P., and Mallet, M.: A NEMO-based model of Sargassum distribution in the Tropical Atlantic , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2663,, 2021.