|Organization of ice flow by localized regions of elevated geothermal heat flux|
|investigators:||M. L. Pittard, B. K. Galton-Fenzi, J. L. Roberts, C. S. Watson|
|journal:||Geophysical Research Letters|
Geothermal flux is one input to a thermo-mechanically coupled ice flow model such as PISM, with significant impact on both ice softness and basal lubrication. Maps of geothermal flux under present-day ice sheets come from nontrivial geophysical inversions, based on seismic and/or magnetic observations, which generate non-unique and (inevitably) smoothed maps. For example, solutions by Shapiro & Fitzwoller (2004) and Fox Maule et al (2005) are familiar to Antarctic ice sheet modelers. However, measurements on ice-free continents show geothermal flux has strong spatial variations including concentrated highs (hot spots).
A model like PISM can, at least, demonstrate the effects on ice flow of small-spatial-scale variations in geothermal flux. This paper studies the Lambert-Amery glacial system in East Antarctica, where a variety of evidence indicates high heat flux regions of at least 120 mW per square meter. Localized regions of elevated geothermal flux are tested in PISM simulations. The results show significant effects on slow-moving ice, with influence extending both upstream and downstream of the geothermal anomaly. Fast-moving ice is relatively unaffected. This contrast suggests that the effect of geothermal flux on ice softness may dominate the lubrication effect.
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.