|Linear sea-level response to abrupt ocean warming of major West Antarctic ice basin|
|investigator:||M. Mengel, J. Feldmann, and A. Levermann|
|journal:||Nature Climate Change|
This paper might best be understood as the second of three studies, by these authors, of three Antarctic ice sheet/shelf basins. These basins are among the biggest and, before studying their properties in detail, the most potentially unstable. But the PISM model results do not suggest all of these basins act the same.
The first of these papers, M. Mengel and A. Levermann (2014) "Ice plug prevents irreversible discharge from East Antarctica", suggests that the Wilkes basin is likely to destabilize under sufficient forcing to remove a certain (quantified) amount of near-ocean ice, but that the time scale of destabilization is long. The third of these papers, J. Feldmann and A. Levermann (2015) "Collapse of the West Antarctic Ice Sheet after local destabilization of the Amundsen Basin", which just appeared in November 2015, demonstrates the fast, and very large in magnitude, destabilization of the whole of WAIS from an Amundsen Sea basin forcing. The current paper suggests that, by contrast, the Filchner-Ronne basin is essentially stable in the sense that the forcing dominates its response.
Ocean models do indicate an abrupt intrusion of warm circumpolar deep water into the cavity below the Filchner–Ronne ice shelf within the next two centuries. The basin's retrograde bed slope would allow for an unstable ice-sheet retreat, but the buttressing of the large ice shelf and the narrow glacier troughs tend to inhibit such instability. This paper's main result, as shown in the graph at left, is that buttressing “wins”. Stronger forcing (“shelf melting”) generates greater ice loss, but there is no tipping point as with the other basins. The response is roughly linear.
As a result of the buzz around Winkelmann et al. (2015)'s modeling of the effect of full conversion of available fossil fuels in the ground into atmospheric CO2, using PISM for determining ice dynamics/response timescale, on 5 October our local paper the Fairbanks Daily News Miner featured PISM. The content is a bit warped by scientist-to-journalist transmission issues, but we are happy to have local recognition of this UAF-lead project!
See the official position announcement here.
We are looking for a candidate who is interested in taking part in the research project “Modelling the ice flow in the western Alps during the last glacial cycle” which is a joint initiative between ETH Zurich and the University of Bern (Prof. Christoph Raible and Dr. Juan Jose Gomez-Navarro). The objective is to better understand the chronology of the last glaciation over the Alps via a modelling approach. The core of this doctoral research will be to model the ice flow and the glacial extent in the western Alps during the last glacial cycle. For that purpose, the PhD student will set up and run the Parallel Ice Sheet Model (PISM) on the clusters of the Swiss National Supercomputing Centre. The crucial step in setting up in PISM will be to include high-resolution climate simulation results, which will be conducted at the University of Bern. The combination of the two state-of-the-art models (ice flow and climate) will give a new insight of the ice flow field prevailing in the western Alpine region during some periods of interest like the last glacial maximum (22000 BP) and an earlier period (65000 BP). The final goal of the PhD will be to compare the new model results to the geomorphological evidence left on the Swiss landscape during the last glacial cycle (e.g. moraines, erratic boulders) in collaboration with quaternary geologists of EHT Zurich. The PhD student will be supervised by Dr. Guillaume Jouvet and Prof. Martin Funk.
The ideal candidate has a master degree either in geophysics, earth sciences, physics, applied mathematics, computer science, or a related field, and a keen interest in modelling of geophysical processes. Previous experience in computer modelling and scientific programming languages (C/C++, Python, Matlab) is an asset. Good writing and communication skills as well as the motivation to fruitfully collaborate within an interdisciplinary framework are essential, in particular with our climate modelling partners at the University of Bern.
For additional information please refer to www.glaciology.ethz.ch or contact Dr. Guillaume Jouvet, firstname.lastname@example.org (no applications).
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.