| ABSTRACT | The North-Western Mediterranean Sea is known as one of the place in the world where open-sea deep convection occurs with the formation of the Western Mediterranean Deep Water (WMDW). At the Winter scale, it is characterized by different phases (preconditioning, strong mixing, restratification and spreading), intense buoyancy loss and strong ocean meso-scale activity. On a longer time scale, it shows a large interannual variability and may be strongly affected by climate change with impacts on the regional ocean circulation, coastal climate and biogeochemistry. Therefore anticipating the future evolution of the WMDW formation remains today a first-class challenge. We try here to tackle this issue for the first time in a multi-model framework. We use the recently-available Med-CORDEX ensemble of coupled and high-resolution Regional Climate System Models (RCSM, Ruti et al. 2016, www.medcordex.eu). The RCSMs are run in a scenario mode driven by ocean and atmosphere lateral boundary conditions coming from CMIP5 GCMs over the period 1950-2100 and under various socio-economic scenario forcings (RCP8.5, RCP4.5, RCP2.6). Using this model ensemble, we characterize the future evolution of the WMDW formation (mixed layer depth, surface of the convective area, dense water volume, deep water hydrology), we assess the multi-model robustness of the signal and we try to disentangle the main drivers of this evolution. |