EGU21-6608, updated on 04 Mar 2021
https://doi.org/10.5194/egusphere-egu21-6608
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Marine ice-sheet experiments with the Community Ice Sheet Model using the MISMIP+ experimental framework. 

Gunter Leguy1, William Lipscomb1, and Xylar Asay-Davis2
Gunter Leguy et al.
  • 1National Center for Atmospheric Research, Boulder, Colorado, USA
  • 2Los Alamos National Laboratory, Los Alamos, New Mexico, USA

Ice sheet models differ in their numerical treatment of dynamical processes. Simulations of marine-based ice are sensitive to the choice of Stokes flow approximation and basal friction law, and to the treatment of stresses and melt rates near the grounding line. We present the effects of these numerical choices on marine ice-sheet dynamics in the Community Ice Sheet Model (CISM). In the experimental framework of the Marine Ice Sheet Model Intercomparison Project (MISMIP+), we compare different treatments of sub-shelf melting near the grounding line. In contrast to recent studies arguing that melting should not be applied in partly grounded cells, it is usually beneficial in CISM simulations to apply some melting in these cells. This suggests that the optimal treatment of melting near the grounding line can depend on ice-sheet geometry, forcing, or model numerics. In the MISMIP+ framework, the ice flow is also sensitive to the choice of basal friction law. To study this sensitivity, we evaluate friction laws that vary the connectivity between the basal hydrological system and the ocean near the grounding line. CISM yields accurate results in steady-state and perturbation experiments at a resolution of ∼2 km (arguably 4 km) when the connectivity is low or moderate, and ∼1 km (arguably 2 km) when the connectivity is strong.

How to cite: Leguy, G., Lipscomb, W., and Asay-Davis, X.: Marine ice-sheet experiments with the Community Ice Sheet Model using the MISMIP+ experimental framework. , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-6608, https://doi.org/10.5194/egusphere-egu21-6608, 2021.

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