OceanIS · Ocean Interaction with Antarctic Ice Shelves

Ocean Interaction with Antarctic Ice Shelves

The primary goal OceanIS is to constrain the contribution of changes in Southern Ocean circulation to the recent acceleration in Antarctic Ice Sheet mass loss. Improving our knowledge of ice shelf–ocean interactions is a critical step toward reducing uncertainty in future sea level rise projections. Ice shelves are coastal areas of floating ice that extend from an ice sheet out over the ocean, and their destabilization can trigger rapid ice discharge. 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. The Southern Ocean overturning entails the upwelling of Circumpolar Deep Water (CDW) offshore Antarctica. The Antarctic Circumpolar Current has shifted poleward, the impact of which, e.g. over the upwelling of CDW, remains unknown. Since CDW is linked to the highest ice shelf thinning rates yet observed, the variability of the CDW properties and its interaction with the ice shelves is the focus of this proposal. To do this, OceanIS integrates, for the first time, several unique data sets, which extend from the deep ocean to the sub–ice shelf environment. Observations show that changes in the thermohaline properties of the Southern Ocean water masses 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 with the largest thermohaline changes 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, OceanIS results suggest East Antarctica is more vulnerable to ocean forcing changes than previously thought. OceanIS provides critical information to guide current ocean/ice sheet models addressing Antarctic Ice Sheet mass loss and rates of sea level change projections.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз