Modelling the water isotope distribution in the Mediterranean Sea using a high-resolution oceanic model (NEMO-MED12-watiso v1.0): evaluation of model results against in situ observations

• Published in: Geoscientific Model Development
• Main Authors: Ayache, Mohamed, Dutay, Jean-Claude, Mouchet, Anne, Tachikawa, Kazuyo, Risi, Camille, Ramstein, Gilles
• Other Authors: Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Modélisation du climat (CLIM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Freshwater and Oceanic Sciences Unit of reSearch (FOCUS), Laboratory of Oceanology, Université de Liège-Université de Liège, Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X), Institut Polytechnique de Paris (IP Paris)-Institut Polytechnique de Paris (IP Paris)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2024
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Western Basin; Planktonic foraminifera
• Online Access: https://hal.science/hal-04691903; https://hal.science/hal-04691903/document; https://hal.science/hal-04691903/file/gmd-17-6627-2024.pdf; https://doi.org/10.5194/gmd-17-6627-2024

International audience Stable water isotopes (δ 18 O w and δD w ) have been successfully implemented for the first time in a high-resolution model of the Mediterranean Sea (NEMO-MED12). In this numerical study, model results are compared with available in situ observations to evaluate the model performance of the present-day distribution of stable water isotopes and their relationship with salinity on a subbasin scale. There is good agreement between the modelled and observed distributions of δ 18 O w in the surface water. The model successfully simulates the observed east-west gradient of δ 18 O w characterising surface, intermediate, and deep waters. The results also show good agreement between the simulated δD w and the in situ data. The δD w shows a strong linear relationship with δ 18 O w (r 2 = 0.98) and salinity (r 2 = 0.94) for the whole Mediterranean Sea. Moreover, the modelled relationships between δ 18 O w and salinity agree well with observations, with a weaker slope in the eastern basin than in the western basin. We investigate the relationship of the isotopic signature of the planktonic foraminifera shells (δ 18 O c ) with temperature and the influence of seasonality. Our results suggest a more quantitative use of δ 18 O records, combining reconstruction with modelling approaches.