A Transient Coupled Ice Flow‐Damage Model to Simulate Iceberg Calving From Tidewater Outlet Glaciers

Abstract

Iceberg calving, the detachment of an ice block at the glacier front, is the main process responsible for the dynamic mass loss from the ice sheets to the ocean. Understanding this process is essential to accurately predict ice sheet response to the future climate. We present a transient multiphysics finite-element model to simulate iceberg break-off and geometry evolution of a marine-terminating glacier. The model solves the coupled equations of ice flow, damage mechanics, oceanic melt, and geometry evolution on the same Lagrangian computational grid. A modeling sensitivity analysis shows that the choice of stress measure used for damage evolution strongly influences the resulting calving front geometries. Our analysis suggests that the von Mises stress measures produce the most realistic calving front geometry evolutions for tidewater glaciers. Submarine frontal melt is shown to have a strong impact on the calving front geometry. The presented multiphysics model includes all processes thus far shown to be relevant for the evolution of tidewater glaciers and can be readily adapted for 3-D and arbitrary bedrock geometries.

How Oceanic Melt Controls Tidewater Glacier Evolution

“…Ma and Bassis () found both an enhancing and a suppressing effect of melt on calving, depending on magnitude and vertical distribution of melt, but their simulation was limited to the onset phase of one calving event. Our own preliminary experiments with a transient Lagrangian ice flow and damage‐based calving model showed similar effects and indicated that the relationship between submarine melt and iceberg calving may not be as straightforward as previously thought (Mercenier et al, ). However, that study lacked a systematic investigation of the influence of oceanic melt rates on calving flux and frontal volume loss.…”

“…We employ the transient Lagrangian multiphysics calving model developed in Mercenier et al () in two and three dimensions. This model is implemented using the libMesh finite element library (Kirk et al, ).…”

“…The damage evolution law (equation ) was tested with different types of stress measure (Mercenier et al, , equation (8)). Damage evolves when the stress measure exceeds a threshold σ th , leading to ice weakening and ultimately failure.…”

“…Damage evolves when the stress measure exceeds a threshold σ th , leading to ice weakening and ultimately failure. From all tested stress measures, only the “von Mises” and “von Mises tensile” stress measures produced realistic calving front geometries and significant calving activity (Mercenier et al, ). The von Mises stress is thus used throughout this study.…”

Contribution of calving to frontal ablation quantified from seismic and hydroacoustic observations calibrated with lidar volume measurements

“…A. Köhler et al: Seismic calving quantification 2012;Köhler et al, 2015), hydroacoustic (Glowacki et al, 2015), and water surface wave monitoring (Minowa et al, 2018).…”