Grounding line migration as response on periodic basal sliding pertubation

• Main Author: Nieschlag, Moritz
• Format: Thesis
• Language: unknown
• Published: 2014
• Subjects: Ice Sheet; Ice Shelf
• Online Access: https://epic.awi.de/id/eprint/42346/; https://hdl.handle.net/10013/epic.49802

This thesis presents results of the response of an artificial ice sheet-ice shelf system to sliding pertubations concerning the grounding line migration. For that subsequent periodic basal slid- ing pertubations are applied on different time scales and geometries using the finite difference full-Stokes model TIM-FD3 . All experiments are performed on a fixed grid. To obtain steady state geometries for the periodic sliding experiments various initial geometries including simple slabs and idealised ones are tested with horizontal resolutions from 10.0, 5.0, 2.5 to 1.25 km to investigate resolution dependencies. The pertubations experiments are examined with three geometries obtained from the geometry spin-up in comparison to applied pertubations on the geometry given by the high-resolution ice model Elmer/Ice. Most pertubation experiments are executed with a grid resolution of 2.5 km and only some with 1.25 km due to computational expenses. The experiments are a continuation of the ice2sea MISMIP3D benchmark puplished by Pat- tyn et al. (2013) at which TIM-FD3 participated. Comparability is given as the geometry of Elmer/Ice was also used for MISMIP3D. Results of the basal sliding experiments indicate that not all experiments show neutral equilib- riums in subsequent basal sliding pertubations. Thus, the grounding line migrates downstream or upstream depending on the position in comparison to the grouding line of Elmer/Ice which appears to be reversible on all resolutions and pertubations. Furthermore the tested steady state geometries show a strong dependency on the horizontal resolution and the chosen initial geometry. They do not converge to the same steady state. This strengthens the importance of the initial geometry for further pertubation experiments.