NEWS: PISM and PETSc 3.7
|Complex Greenland outlet glacier flow captured|
|investigators:||A. Aschwanden, M. Fahnestock, and M. Truffer|
The paper is based on PISM simulations of 600 m grid resolution over the entire Greenland ice sheet. All parts of the ice sheet, and each outlet glacier in particular, see the same physics. The quality of this flow model for 29 major outlet glaciers is assessed by comparison with present-day-observed surface velocities at cross-flow near-ocean profiles, often called “flux gates”. The main result is that the majority of the outlet glaciers show strong correlation between modeled and observed velocity. The paper demonstrates that outlet glacier flow can be captured with high fidelity if ice thickness is well-constrained and if vertical shearing as well as membrane stresses are included in the model. While it is not clear that solving the full-stress configuration would improve the fit, it is clear that the shallow hybrid model can be applied at higher resolution and for longer-duration runs. Inversion of surface properties for individual glaciers is not essential to reproduce the overall flow pattern. Spatial variability in flow can be explained in large part by the spatial variability in ice thickness.
The Paleoclimate Dynamics section at Alfred-Wegener-Institut invites applications for a position as a
with a background in ice sheet or climate modelling for the DFG-project “Global sea level change since the Mid Holocene” (SPP 1889).
Background and tasks:
The aim of this project is to study the evolution of polar ice sheets of the last 6000 years and to estimate the role of climate – ice sheet interactions. Combining climate and ice sheet simulations of different resolution, the project particularly focusses on the ice sheets' mass balance and on ice shelf – ocean interactions under natural and anthropogenic climate change.
The postdoc’s duties will include set-up, supervision, and analysis of climate and ice sheet (PISM) simulations as well as publication in peer-reviewed journals.
The successful candidate should have a PhD in glaciology, atmospheric sciences, oceanography or related sciences and should have a background in either ice sheet or climate modelling.
The position is limited to 3 years, starting August 1st, 2016 or later. The salary will be paid in accordance with the German Tarifvertrag des öffentlichen Dienstes (TVöD Bund), salary level 13. The place of employment will be Bremerhaven.
For further information:
PETSc 3.7 was released on April 25, 2016. We are currently working on making PISM compatible with PETSc 3.7 and will announce it here as soon as possible.
In the meantime, please install petsc 3.6.4 from here. PISM version 0.7 (
stable0.7 branch) works with any PETSc 3.5.X and higher.
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.