Indications of the Ronne-Filchner-Ice-Shelf becoming host to a warm cavity within the second half of the 21st century under high emission scenario

To quantify the ocean-driven Antarctic ice mass loss and the subsequent sea level rise, the geophysical modeling community is pushing towards frameworks that fully couple increasingly complex models of atmosphere, ocean, sea ice and ice sheets & shelves. We will present results from an 8km ocean – ice shelf – ice sheet - bathymetry coupled model of Antarctica, based on the frameworks of the Regional Ocean Modelling System and the Parallel Ice Sheet Model.

Our projections for two different global warming trajectories (rcp2.6 & 8.5) suggest that warming of the Antarctic shelf seas diverge between scenarios from the 2050s onward. Our preliminary analysis focuses on the two largest ice shelves, the Ross and the Ronne-Filchner, both currently hosting cold ocean cavities.

Under the rcp8.5 trajectory, episodic warm water hosing over the eastern shelf in the Weddell Sea becomes a permanent feature at mid century, leading to a 1.5 degree increase of water temperature within a decade over the central and the eastern shelf. Basal melt rates of the entire Filchner-Ice-Shelf and the southern Ronne-Ice-Shelf exceed 2 m/yr, which in some areas is a magnitude larger than current rates.
In contrast the Ross-Ice-Shelf appears to remain stable under both climate trajectories. In the rcp8.5 scenario the shelf sea over the north-south stretching banks warms moderately by 0.25-0.5 degrees but this increased heat has no access to the cavity according to our model results.
We will present insight to the mechanisms that drive the sudden warming in the Weddell Sea and construct a hypothesis of why the Ross Ice Shelf appears more protected from Southern Ocean heat.