|Repeated large-scale retreat and advance of Totten Glacier indicated by inland bed erosion|
|investigators:||A. Aitken and others|
The East Antarctic Ice Sheet (EAIS) has been more stable than the other major ice sheets for at least a million years. However, for older warm periods there is evidence suggesting collapse of the Totten Glacier, one of several large, ocean-forced outlets of the EAIS, with retreat into interior basins. This paper shows that deep ice-sheet erosion has occurred in two regions, one at the present-day head of the Glacier and the other deep within the subglacial basin behind it. Aerogeophysical data suggest two distinct configurations, a “modern” ice sheet with a near-present-day margin, and a retreated configuration. The transitional region between these is less eroded, suggesting shorter-lived exposure to repeated retreat–advance events.
What is a role for PISM is such work? In this case, ice-sheet modelling indicates that the sector's retreat-driven global sea-level increase could 0.9 meters in modern-like configurations, with a jump up to 2 meters or more if there is a transition to the retreated configuration.
The 4000 square km ice field in Southeast Alaska is well-known and accessible since its outlets are in the suburbs of the Alaska state capital, Juneau. But climate data for the area are sparse.
Those model runs that agreed well with observations for 1971 to 2010 generated volume and area losses of more than half by 2099. While co-author Regine Hock (UAF) is quoted as saying “The massive icefield that feeds Alaska’s Mendenhall Glacier may be gone by 2200 if warming trend predictions hold true,”, the authors emphasize that spatially-distributed mass balance measurements and improved climate projections that resolve the local temperature and precipitation patterns are essential to solidifying these predictions.
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PISM is jointly developed at the University of Alaska, Fairbanks (UAF) and the Potsdam Institute for Climate Impact Research (PIK). For more about the team see the UAF Developers and PIK Developers pages.
UAF developers, who are in the Glaciers Group at the GI, are supported by NASA's Modeling, Analysis, and Prediction and Cryospheric Sciences Programs (grants NAG5-11371, NNX09AJ38C, NNX13AM16G, NNX13AK27G) and by the Arctic Region Supercomputing Center.