The Southern Ocean Freshwater Input from Antarctica (SOFIA) Initiative aims to improve our understanding of the simulated response to Antarctic freshwater input, and in particular the model uncertainty. The initiative has developed an experimental protocol and is engaging with modelling groups from around the world to run this common set of experiments using a variety of coupled climate and ocean-only models. Data from this international multi-model ensemble is openly shared for analysis, and is being synthesized into a series of publications by SOFIA participants. Full details are provided at https://doi.org/10.5194/gmd-16-7289-2023 GET DATA: https://sofiamip.github.io/data-access.html

Here, we present new, transient, GCM-forced ice-sheet simulations validated against proxy reconstructions. This is the first time such an evaluation has been attempted. Our empirically constrained simulations indicate that the AIS contributed 4 m to global mean sea level by 126 ka BP, with ice lost primarily from the Amundsen, but not Ross or Weddell Sea, sectors. We resolve the conflict between previous work and show that the AIS thinned in the Wilkes Subglacial Basin but did not retreat. We also find that the West AIS may be predisposed to future collapse even in the absence of further environmental change, consistent with previous studies. There are two files, for Termination 1 ('T1') and Termination 2 ('T2'). They contain spatial fields for ice thickness, ice surface elevation, bedrock elevation, surface and basal velocity, and mask. The T1 outputs are every 500 years, whereas the T2 outputs are every 100 years. The spatial resolution of both is 20 km. Sea-level-equivalent mass loss can be calculated from these outputs, but is also provided here in a text file for convenience. RELATED PUBLICATION: Golledge, N.R., Clark, P.U., He, F., et al. (2021). Retreat of the Antarctic Ice Sheet During the Last Interglaciation and Implications for Future Change. Geophysical Research Letters, 48(17). https://doi.org/10.1029/2021GL094513 GET DATA: https://doi.org/10.17605/OSF.IO/GZB3H

Global mean sea level has risen at an accelerating rate in the last decade and will continue to rise for centuries. The Amundsen Sea Embayment in West Antarctica is a critical region for present and future ice loss, however most studies consider only a worst-case future for the region. Here we use ice sheet model sensitivity experiments to investigate the centennial scale implications of short-term periods of enhanced ocean driven sub-ice shelf melting on ice loss and assess what future reduction in melting is necessary to mitigate ice stream retreat and offset global sea level rise. Our findings reveal that restoring elevated melt rates to present-day levels within 100 years causes rates of ice discharge to immediately decline, thereby limiting the overall sea level contribution from the region. However, while ice stream re-advance and slowed ice discharge is possible with reduced basal melting, a centennial scale increase in accumulation must occur to offset the extensive ice loss. Further details are provided at: Alevropoulos-Borrill, A., Golledge, N.R., Cornford, S.L. et al. Sustained ocean cooling insufficient to reverse sea level rise from Antarctica. Commun Earth Environ 5, 150 (2024). https://doi.org/10.1038/s43247-024-01297-8 GET DATA: https://doi.org/10.17605/OSF.IO/UYMA6

Data of apparent ice thickness from airborne electromagnetic (AEM) surveys of fast ice in McMurdo Sound, Antarctica, carried out in Nov/Dec 2009, 2011, 2013, 2016, and 2017. Values are given for apparent thicknesses derived from both, in-phase and quadrature signals. The difference between both thicknesses is a scaled measure of sub-ice platelet layer thickness. Data are from east-west transects across McMurdo Sound, at fixed latitudes. Data were smoothed and interpolated onto a regular longitude grid (0.001 degree increments). More information can be found in Haas et al. (2021). Related Publication: Haas, C., Langhorne, P. J., Rack, W., Leonard, G. H., Brett, G. M., Price, D., Beckers, J. F., and Gough, A. J.: Airborne mapping of the sub-ice platelet layer under fast ice in McMurdo Sound, Antarctica, The Cryosphere, 15, 247–264, https://doi.org/10.5194/tc-15-247-2021, 2021