Status: this preprint was under review for the journal TC but the revision was not accepted.
Full-Stokes modeling of grounding line dynamics, ice melt and iceberg calving for Thwaites Glacier, West Antarctica
Hongju Yu,Eric Rignot,Mathieu Morlighem,and Helene Seroussi
Abstract. Thwaites Glacier (TG), West Antarctica, has been losing mass and retreating rapidly in the past three decades. Here we present a two-dimensional, Full-Stokes (FS) modeling study of the grounding line dynamics and iceberg calving of TG. First, we compare FS with two simplified models, the higher-order (HO) model and the shallow-shelf approximation (SSA) model, to determine the impact of changes in ice shelf basal melt rate on grounding line dynamics. Second, we combine FS with the Linear Elastic Fracture Mechanics (LEFM) theory to simulate crevasse propagation and iceberg calving. In the first experiment, we find that FS requires basal melt rate consistent with remote sensing observations to reach steady state at TG’s current geometry while HO and SSA require unrealistically high basal melt rate. The grounding line of FS is also more sensitive to changes in basal melt rate than HO and SSA. In the second experiment, we find that only FS can produce surface and bottom crevasses that match radar sounding observations of crevasse width and height. We attribute the difference to the non- hydrostatic conditions of ice near the grounding line, which facilitate crevasse formation and are not accounted for in HO and SSA. Additional experiments using FS indicate that iceberg calving is significantly enhanced when surface crevasses exist near the grounding line, when ice shelf is shortened, or when the ice shelf front is undercut. We conclude that FS yields substantial improvements in the description of ice flow dynamics at the grounding line under high basal melt rate and in constraining crevasse formation and iceberg calving.
How to cite. Yu, H., Rignot, E., Morlighem, M., and Seroussi, H.: Full-Stokes modeling of grounding line dynamics, ice melt and iceberg calving for Thwaites Glacier, West Antarctica, The Cryosphere Discuss. [preprint], https://doi.org/10.5194/tc-2016-101, 2016.
Received: 25 Apr 2016 – Discussion started: 24 May 2016
We performed a 2D Full-Stokes (FS) modeling study of grounding line dynamics and calving of Thwaites Glacier, West Antarctica. We compare FS with simplified models on grounding line migration and we combine FS with Linear Elastic Fracture Mechanics to simulate crevasse propagation. We find that only FS is able to provide reliable grounding line migration and to explain observed crevasse. We conclude that it may be essential to employ FS in the grounding line region for 2D simulations.
We performed a 2D Full-Stokes (FS) modeling study of grounding line dynamics and calving of...