Integration of climate and ice sheet model simulations with the Roosevelt Island Climate Evolution (RICE) ice core record for the last deglaciation
Abstract
A main uncertainty of future sea level rise is the stability of the West Antarctic Ice Sheet (WAIS). The Roosevelt Island Climate Evolution (RICE) Project aims to constrain the sensitivity of the Ross Ice Shelf, the main drainage pathway of WAIS, to past climatic changes using a deep ice core drilled at Roosevelt Island, a grounded ice dome located at the north-eastern edge of the Ross Ice Shelf. Given its proximity to the Ross Sea, chemistry data from the ice core provide insight into past oceanic and ice sheet changes, including sea ice coverage, marine productivity, ice shelf extent and grounding line position over the last deglacial period (18 ka to present day). Additionally, changes in atmospheric circulation, cyclonic activity and katabatic winds are also reconstructed to provide a detailed view of the Ross Ice Shelf climate history. Here we apply a combination of transient climate model simulations (TraCE-21ka and LOVECLIM) and climate-forced ice sheet model experiments using the Parallel Ice Sheet Model (PISM) to test hypotheses based on interpretations from the ice core record and to better understand the mechanisms controlling the observed changes. In particular, we assess the spatial and temporal relationships between Southern Ocean conditions (e.g., sea ice concentration, sea surface temperatures) and accumulation and temperature at Roosevelt Island. The climate models demonstrate a clear climatic shift in the early Holocene attributed to a weakening in the Amundsen Sea Low and reduced sea ice concentration, the timing of which coincides with an isotopic shift in the ice core record. The climate-forced ice sheet model experiments are applied to better constrain both the timing of grounding line retreat and ice shelf formation as well as test their sensitivity to changes in atmospheric and ocean conditions. The simulations show ice shelf formation occurring in the early to mid-Holocene and grounding line retreat by Roosevelt Island to the modern-day position along Siple Coast in the mid- to late Holocene. The RICE ice core record, in combination with other Antarctic ice core records, also highlights key model biases that require further exploration, including the representation of periods of abrupt climate change, such as the Antarctic Cold Reversal and the Meltwater Pulse 1a and 1b events.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.C41C1773L
- Keywords:
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- 3337 Global climate models;
- ATMOSPHERIC PROCESSESDE: 0724 Ice cores;
- CRYOSPHEREDE: 1621 Cryospheric change;
- GLOBAL CHANGEDE: 4901 Abrupt/rapid climate change;
- PALEOCEANOGRAPHY