TY  - JOUR
AU  - Durand G, Gagliardini O.
PY  - 2009//
TI  - Marine ice sheet dynamics: Hysteresis and neutral equilibrium
T2  - J. Geophys. Res.
JO  - J. Geophys. Res.
SP  - F03009 -
VL  - 114
IS  - F3
PB  - AGU
KW  - marine ice sheet
KW  - grounding line
KW  - full Stokes modeling
KW  - 0774 Cryosphere: Dynamics
KW  - 0726 Cryosphere: Ice sheets
KW  - 0728 Cryosphere: Ice shelves
KW  - 0798 Cryosphere: Modeling
KW  -
N2  - The stability of marine ice sheets and outlet glaciers is mostly controlled by the dynamics of their grounding line, i.e., where the bottom contact of the ice changes from bedrock or till to ocean water. The last report of the Intergovernmental Panel on Climate Change has clearly underlined the poor ability of models to capture the dynamics of outlet glaciers. Here we present computations of grounding line dynamics on the basis of numerical solutions of the full Stokes equations for ice velocity, coupled with the evolution of the air ice– and sea ice–free interfaces. The grounding line position is determined by solving the contact problem between the ice and a rigid bedrock using the finite element code Elmer. Results of the simulations show that marine ice sheets are unstable on upsloping beds and undergo hysteresis under perturbation of ice viscosity, confirming conclusions from boundary layer theory. The present approach also indicates that a 2-D unconfined marine ice sheet sliding over a downsloping bedrock does not exhibit neutral equilibrium. It is shown that mesh resolution around the grounding line is a crucial issue. A very fine grid size (<100 m spacing) is needed in order to achieve consistent results.
SN  - 0148-0227
UR  - http://dx.doi.org/10.1029/2008JF001170
N1  - exported from refbase (http://publi.ipev.fr/polar_references/show.php?record=1877), last updated on Wed, 03 Jul 2024 13:30:47 +0200
ID  - DurandG2009
ER  -