On the Link between the Southern Ocean Fronts and Antarctic Ice Shelves Thinning

Improving our knowledge of ice shelf–ocean interactions is a critical step toward reducing uncertainty in future sea level rise projections. It is now evident that ocean–driven basal melt is the major cause of ice loss from Antarctica’s fringing ice shelves. However much of the fundamental dynamics of how the ocean delivers heat to the ice shelves remains unresolved.

Progress in this area requires bringing together the fields of ice shelf–ocean interactions and large–scale Southern Ocean oceanography. One way forward is constraining the contribution of changes in Southern Ocean circulation to the recent acceleration in Antarctic Ice Sheet mass loss. Using a combination of data sets (altimetry, hydrography and ice shelf thinning estimates), we document the variability of the CDW properties (upwelling location, temperature and salinity) and its link to Antarctic ice shelves’ thinning rates.

Observations show that changes in the thermohaline properties of CDW over the last 20 years are consistent with a southward shift of warm CDW towards the Antarctic continent. Our results also show that the areas where CDW upwells closer to the continental break coincide with the regions where Antarctic ice shelves are melting the fastest, especially in East Antarctica. East Antarctica has long been thought to be a stable part of Antarctica. However, our results suggest East Antarctica is more vulnerable to ocean forcing changes than previously thought.