NEWS: PISM at AGU 2014
The Parallel Ice Sheet Model pism0.6 is an open source, parallel, high-resolution ice sheet model. Features:
Surface velocity, calculated fracture density, and modeled flow results for Filchner Ice Shelf. Click the image to go to The Cryosphere article page.
|Fracture-induced softening for large-scale ice dynamics|
|investigators:||T. Albrecht and A. Levermann|
Fracture processes within ice shelfs have been observed to reduce the retentive forces of the shelves on the Antarctic ice sheet. This paper adds a continuum representation of fractures, and their evolution, to PISM, and applies it to several major ice shelves in Antarctica. A key addition is the introduction of a higher-order scheme for advecting the two-dimensional fracture density field. Fractures and ice flow are coupled through a reduction of modeled ice viscosity proportional to the fracture density, so fracture-induced softening can feed back to cause added shear and self-amplified fracturing. The results of the simulations are compared to observations. Observed sharp across-flow velocity gradients in fracture-weakened regions are reproduced. This fracture-softening model is a basis for a future model of enhanced fracture-based calving.
In a Geoscientific Model Development Discussion paper, UAF author Ed Bueler and IMAU author Ward Van Pelt describe PISM's new mass conserving subglacial hydrology models.
For the PISM user with an interest in subglacial hydrology this paper provides a detailed description of all the subglacial hydrology models available in PISM versions v0.6 and above, along with a stability analysis, verification, and an application to the Greenland ice sheet.
Only fixes and improvements that should not break existing functionality are included in this release. We recommend updating from v0.6 unless you have a good reason against it. Upgrade by doing “git pull” in the PISM source tree. (Or get a new tagged “.tar.gz” or “.zip” at github.com/pism/pism/releases.) Then do “make install” in the build directory.
For a full list of changes since v0.6, please see https://github.com/pism/pism/blob/stable0.6/CHANGES.md
Send email to email@example.com for help with any version of PISM.
PISM is jointly developed at the University of Alaska, Fairbanks (UAF) and the Potsdam Institute for Climate Impact Research (PIK). 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.