This study examines the processes controlling interannual salinity variability on the Ross Sea continental shelf in a high-resolution regional coupled ocean-sea ice-ice shelf model with climatological monthly boundary conditions. We show that both brine rejection and salt transport influence this variability. The surface salinity is influenced by brine-rejection and the upper layer water import across the shelf break. Enhanced sea ice production does not necessarily increase the salinity in High Salinity Shelf Water (HSSW). This is because the brine-rejection induced salt input into the lower layer cannot exceed the salt export through HSSW outflow when the surface salinity is relatively low and the vertical salt gradient is relatively large. The East–West sea level pressure gradient across the Ross Sea significantly shapes the surface winds and controls sea ice production on the shelf. Increased HSSW production and salinity can raise the outflow of saltier lower layer water and inflow of the upper layer water across the shelf break, tending to amplify the vertical salt gradient on the shelf. Thus, wind-forced brine rejection drives the interannual salinity variability, while the responding overturning circulation, modulated by wind forcing to some extent, tends to dampen it. However, a more complete understanding of interannual salinity variability also requires considering the variability in the properties of the upstream water of the Ross Sea continental shelf. This study provides a more comprehensive analysis of the mechanisms driving interannual salinity variability, shedding light on understanding the observed salinity variability and trend on the Ross Sea continental shelf.

Ross Sea,coupled model,High Salinity Shelf Water