Elmer/Ice News

Print

Elmer/Ice @ AGU2016

Written by Olivier Gagliardini on .

aguDon't miss the 14 presentations using Elmer/Ice at the next AGU! These contributions clearly show the high variety of applications that can be solved using Elmer/Ice by a growing number of groups all around the world!

Monday, 12 December 2016 - 13:40 - 18:00 - Moscone South - Poster Hall
C13C Observing and Understanding Changes in Polar Ice Sheets and Glaciers Using Ground, Airborne, and Satellite Remote Sensing II Posters

C13C-0835: Seasonal variability in ice-front position, glacier speed, and surface elevation at Helheim Glacier, SE Greenland, from 2010-2016. Kehrl L., I. Joughin and D. Shean

Tuesday, 13 December 2016 - 08:00 - 12:20 - Moscone South - Poster Hall
C21B Modeling of the Cryosphere: Glaciers and Ice Sheets I Posters
C21B-0669 A model of damage for the SSA : Assessing the influence of damage on the grounding line dynamics. Gillet-chaulet F., J. Brondex, O. Gagliardini1 and G. Durand

C21B-0672 A fully coupled transient thermomechanical ice-flow/permafrost model of the Rhine Glacier, Switzerland: effects of permafrost on basal conditions. Cohen D. and T. Zwinger

C21B-0682: Temporary grounding line stabilization on a retrograde bed due to ice plain formation. Jong L., R. Gladstone, B. Galton-Fenzi and M. King

C21B-0685: Investigating the Role of Buoyancy in Tidewater Glacier Iceberg Calving Dynamics. Trevers M., A. Payne and S. Cornford

C21B-0688: Ice-sheet Temperature Around Subglacial Lake Vostok Constrained by New Flowband Modeling. Kintner P., D. Winebrenner and M. Koutnik

C21B-0689: Simulating ice shelf response to potential triggers of collapse. Huth, A. and B.E. Smith

Wednesday, 14 December 2016 - 08:00 - 12:20 - Moscone West - 3007
C31C: Modeling of the Cryosphere: Glaciers and Ice Sheets II and III
8:00-8:15: C31C-01 Results from ISOMIP+ and MISOMIP1, two interrelated marine ice sheet and ocean model intercomparison projects (Invited). Xylar Asay-Davis et al.

9:00-9:15: C31C-05 Results of the Greenland Ice Sheet Model Initialisation Experiments ISMIP6 – initMIP-Greenland. Heiko Goelzer et al.

9:15-9:30: C31C-06 A Hydro-Mechanical Flow Line Model for Simulating Surge Behaviour of Variegated Glacier, Alaska. van Geffen S. and J. Oerlemans

11:05-11:20: C32A-04 How Much Evolving Basal Friction Affects Grounding Line Dynamics ? Brondex J., O. Gagliardini, F. Gillet-chaulet and G. Durand

Friday, 16 December 2016 - 08:00 - 10:00 - Moscone West - 2020
C51E Exploration, Observation, and Modeling of Fast-Moving Glaciers, Ice Sheets, and Permafrost Landscapes I

8:15-8:30: C51E-02: Crevasses as indicators of surge dynamics in the Bering Bagley Glacier System, Alaska: Numerical experiments and comparison to image data analysis. Trantow T. and U. Herzfeld

Friday, 16 December 2016 - 08:00 - 10:00 - Moscone West - 3007
C51G Glacier Response to Climate Change I
9:15-9:30: C51G-06: Examining model hierarchies of glacier response to climate. Christian J., M. Koutnik and G. Roe

Friday, 16 December 2016 - 13:40 - 18:00 - Moscone South - Poster Hall
C53B Exploration, Observation, and Modeling of Fast-Moving Glaciers, Ice Sheets, and Permafrost Landscapes II Posters
C53B-0720: New approaches to observation and modeling of fast-moving glaciers and ice streams. Herzfeld et al.

Print

Form of the basal friction law under PIG

Written by Olivier Gagliardini on .

PIG Fabien2016In ice-sheet models, slip conditions at the base between the ice and the bed are parameterized by a friction law. The most common relation has two poorly constrained parameters, C and m. The basal slipperiness coefficient, C, depends on local unobserved quantities and is routinely inferred using inverse methods. While model results have shown that transient responses to external forcing are highly sensitive to the stress exponent m, no consensus value has emerged, with values commonly used ranging from 1 to infinity depending on the slip processes. By assimilation of Pine Island Glacier surface velocities from 1996 to 2010, we show that observed accelerations are best reproduced with m>5. We conclude that basal motion, in much of the fast flowing region, is governed by plastic deformation of the underlying sediments. This implies that the glacier bed in this area cannot deliver resistive stresses higher than today, making the drainage basin potentially more sensitive to dynamical perturbations than predicted with models using standard values m = 1 or 3.

More informations: Gillet-Chaulet, F., G. Durand, O. Gagliardini, C. Mosbeux, J. Mouginot, F. Rémy, and C. Ritz, 2016. Assimilation of surface velocities acquired between 1996 and 2010 to constrain the form of the basal friction law under Pine Island Glacier, Geophys. Res. Lett., 43, doi:10.1002/2016GL069937.

 

 

Print

Sensitivity of Barnes Ice Cap to climate state and internal dynamics

Written by Olivier Gagliardini on .

gilbert2016Barnes Ice Cap is a remnant of the Laurentide Ice Sheet, which covered much of northern North America during the Last Glacial Maximum. Barnes reached a quasi-equilibrium state ~2000 years ago and has remained similar in size since then, with a small increase during the Little Ice Age. In this study, we combine historical observations (1960–1980) with more recent satellite and airborne data (1995–2010) to drive a mass balance model coupled to a transient thermomechanical model with an adaptive mesh geometry. The model is used to characterize the current state of the ice cap and to investigate its stability as a function of climate and its own internal dynamics. On millennial time scales we show that ice flow is influenced by adjustment of an unsteady shape, by gently sloping bedrock, and by contrasting viscosities between the Pleistocene and Holocene ice. On shorter time scales, Barnes is affected by surge activity. Sensitivity tests reveal that Barnes experienced climate conditions which enabled its stability 2000 to 3000 years ago but will disappear under current climate conditions in the next millennium.

More information : Gilbert, A., G. E. Flowers, G. H. Miller, B. T. Rabus, W. Van Wychen, A. S. Gardner, and L. Copland, 2016. Sensitivity of Barnes Ice Cap, Baffin Island, Canada, to climate state and internal dynamics, J. Geophys. Res. Earth Surf., 121(8), 1516–1539, doi:10.1002/2016JF003839.

Elmer / Ice project © 2012 -- Conception : iGrafic