The idealised Southern Ocean response to freshwater distribution
Patrick James Brett
Authors:
Patrick Brett(1,2), Ariaan Purich(1,2)
Affiliations:
(1) Monash University, Victoria, Australia, (2) Research Initiative for Securing Antarctica’s Environmental Future (SAEF)
Abstract:
Changes in the Antarctic mass balance are predicted to drive accelerated meltwater release into the Southern Ocean over the coming century. The resulting freshening of the Southern Ocean will lead to local changes in ocean stratification, circulation, sea ice, with the capacity to alter the trajectory and pattern of future climate change. However, coupled climate models do not presently simulate dynamic ice sheets and shelves, leading to significant uncertainty in future projections. Investigating the response of the Southern Ocean to meltwater input is critical to quantifying this uncertainty. To date, the role of freshwater distribution remains poorly constrained. Here we use ACCESS-ESM1.5 to investigate the sensitivity of the climate response to different freshwater distributions in idealised experiments. Following the experimental framework of the Southern Ocean Freshwater Input from Antarctica (SOFIA), we find differences in water properties along the Antarctic continental shelf between different freshwater distributions. Compared to runs with freshwater forcing concentrated around the Antarctic coast, when freshwater forcing is spread north to 60°S, a stronger reduction in deep-ocean convection and stronger Southern Ocean surface cooling is simulated. Our results suggest how freshwater is spatially distributed in models may be an important factor to consider when analysing the climate response.
Audience:
Primarily the Antarctic and Southern Ocean science session, but the results may also be interesting to all Working Groups
Keywords:
Southern Ocean, Ice Shelves, Meltwater, Sea ice, Ocean dynamics, Meltwater distribution
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