Determining Ocean Tide Influences on Antarctic Ice Shelf Circulation Using GFDL MOM6

Antarctic ice shelves are the floating extensions of the Antarctic ice sheet, slowing the flow of glacial ice into the surrounding ocean and mitigating the rate of sea level rise. Because ice shelves are in direct contact with the ocean, they are vulnerable to increases in ocean temperature (Gille, 2002), tidal amplitude (Wilmes et al., 2017), and changes in salinity (Haumann et al., 2016) associated with climate change, especially in the West Antarctic.

This study implements a diurnal tidal forcing in an idealized ice-shelf configuration of the Modular Ocean Model 6 (MOM6) to investigate the sensitivity of ice-shelf mass balance to changes in ocean temperature, salinity, tidal amplitude, and tidal phase. We simulate a warm shelf configuration with an evolving shelf boundary fully coupled to the ocean, varying the horizontal resolution to ¼, ½, 1, and 4 km to further investigate the impact of eddies on sub-ice-shelf circulation and mass balance. Shelf melt rate consistently increases while tidal forcing is present. We expect that under higher ocean temperatures and decreased salinity, melt rates will remain largely unchanged, while overturning circulation strength within the cavity decreases. Increasing alongshore and cross-shore tidal amplitude should increase melt rate.