Antarctic Ice Sheet sensitivity to environmental forcing in the Holocene
Abstract
Although modern observations suggest a link between warming oceanic conditions and Antarctic ice sheet grounding-line retreat, the role of environmental forcing in past grounding-line retreat is unclear. Here, we present the results of two ice sheet model ensembles using the Parallel Ice Sheet Model (PISM) that investigate ice sheet sensitivity to ocean and atmosphere forcing. Constrained by geological and paleoclimate proxy data, the first ensemble focuses on deglacial ice sheet retreat in the Ross Embayment, Antarctica's largest catchment. The results demonstrate that while the atmosphere forcing influences the initial timing of grounding-line retreat, ocean forcing becomes the dominant control on grounding-line migration through the Holocene following the formation and expansion of the Ross Ice Shelf. Through this time interval, the grounding-line position is sensitive to small changes in basal melt rates of the ice shelf. The second ensemble is based on the projection experiments of the Ice Sheet Model Intercomparison Project 6 (ISMIP6) of the next century. In this ensemble, we systematically explore unconstrained model parameters to assess their influence on the full continental-scale ice sheet response to climate forcing. The results highlight the sensitivity of Antarctic ice shelves to changes in basal melt rates, driven by changes in ocean temperature and salinity. Together, these two ice sheet model ensembles indicate the continuity of ocean thermal forcing as the key driver of Antarctic grounding-line retreat.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMC024...01L
- Keywords:
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- 0726 Ice sheets;
- CRYOSPHERE;
- 0730 Ice streams;
- CRYOSPHERE;
- 1105 Quaternary geochronology;
- GEOCHRONOLOGY;
- 1621 Cryospheric change;
- GLOBAL CHANGE