The aim of this study is to better understand the different overriding mechanisms that control the evolution of the temperature in the Bay of Biscay, through realistic simulations over a period of 50 years. Based on the work of Michel et al. (2009) on the variability of temperature in the Bay of Biscay (Fig1). We will extend the understanding of the interannual variability to the haline contents and the circulation at regional scale. Here we compare two global simulations, ORCA-G70 and ORCA-GRD100 (¼°resolution), that differs mainly in the vertical resolution and we show their variability.