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Ice sheet melting into the Southern Ocean can change the formation and properties of the Antarctic Bottom Water (AABW). Ocean models often mimic ice sheet melting by adding freshwater fluxes in the Southern Ocean under diverse spatial distributions. We use a global ocean and sea-ice model to explore whether the spatial distribution and magnitude of meltwater fluxes can alter AABW properties and formation. We find that a realistic spatially varying meltwater flux sustains AABW with higher salinities compared to simulations with uniform meltwater fluxes. Finally, we show that increases in ice sheet melting above 12% since 1958 can trigger AABW freshening rates similar to those observed in the Southern Ocean since 1990, suggesting that the increasing Antarctic meltwater discharge can drive the observed AABW freshening. more...

Ocean heat transport towards Antarctica directly drives the melting of Antarctic ice shelves, modulating sea level rise and the formation of Antarctic Bottom Water. A common dynamical assumption is that heat transport across the Antarctic continental slope is modulated by the strength of the Antarctic Slope Current (ASC), which is thought to act as a barrier to cross-slope heat transport. However, observations of the ASC are too scarce to investigate its relationship to poleward heat transport across large circumpolar spatial scales, or over long temporal scales. Also, until recently, ocean models lacked the spatial resolution required to accurately represent the ASC or the eddy heat transport onto the Antarctic shelf. In this study, we analyze the relationship between the ASC and the cross-slope heat transport in a circumpolar, eddy-rich ocean and sea ice simulation. We find that the local strength of the time-mean ASC is not a good predictor of local cross-slope heat transport, i.e., spatial variability in the ASC is not related to spatial variability in poleward heat transport. However, there is a relationship between ASC strength and cross-slope heat transport in the temporal domain. We quantify the strength of the relationship across different time scales (sub-seasonal, seasonal and interannual) and across varying model resolution (from 1/10º to 1/20º to 1/40º)., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023) more...

Simulation FW61 produced with the oxygen-isotope enabled University of Victoria Earth System Model. The simulation starts 9 kiloyears before the present (...-0949.01.01.nc) and runs until 7 kiloyears before the present. The outputs are annual means (tsi) and annual fields (tavg).&nbsp more...

Simulation for the 8.2 Ka event before the present, using the University of Victoria Earth System Climate Model, Version 2.9. The simulation starts 9 kiloyears before the present (...-0949.01.01.nc) and runs until 7 kiloyears before the present. The outputs are annual means (tsi) and annual fields (tavg). Please cite the original paper accordingly. Journal Publication DOI:https://doi.org/10.1016/j.quascirev.2020.106498 more...