On the ability of OMIP models to simulate the ocean mixed layer depth and its seasonal cycle in the Arctic Ocean

We evaluate the skills of ocean–sea ice general circulation models involved in the Ocean Modeling Intercomparison Project in simulating the ocean mixed layer depth and its seasonal cycle in the Arctic region. During summer months, all models consistently underestimate the mixed layer depth compared to observational data from the Monthly Isopycnal Mixed layer Ocean Climatology and the Ice Tethered Profilers. In fall and winter, the models exhibit great variability compared to observational data, and inter-model comparison reveals differences up to several tens of meters. We analyze the origin of the fall and winter model biases in ice-covered regions, where the seasonal cycle of the surface salinity and mixed layer depth is strongly influenced by brine rejection resulting from ocean–sea ice interactions.