Feedback between Antarctic ice-shelf melt and Southern Ocean surface warming


May 31, 2021

13 h on teams

Feedback between Antarctic ice-shelf melt and Southern Ocean surface warming by Charles Pelletier (UCLouvain)

Antarctic ice shelves are a unique feature of the Southern polar region. They consist in potentially large (i.e. larger than most European
countries) floating glaciers, mechanically linked to the rest of the Antarctic ice sheet from above, but also directly connected to the
Southern Ocean from below within what is called "ice shelf cavities". In these cavities, the relatively warm ocean is in direct contact with the
ice sheet, which then injects cold and fresh meltwater at depth. While this ocean-impacting phenomenon has been identified decades ago,
representating it within numerical models is a much more recent endeavor. In this talk we will present our first investigations on the
potential feedback between a hypothetical Southern Ocean surface warming due to increased radiation, and the action of ice shelf meltwater. In
other words, how does the presence of ice shelf cavities affect the reaction of the Southern Ocean to a surface warming that can be expected
from global climate change? Does the presence of ice shelf cavities trigger thermodynamical mechanisms which make the ocean even warmer than
if cavities did not exist? Or does it stabilize the pertubation and bring temperatures back to "normal"? While the complexity of the
Southern Ocean prevents any global and definitive conclusions to be established, the different behaviors across basins suggest that the response conceals distinct physical phenomena, and greatly depends on
the nature of the water masses reaching the Antarctic continental shelf.