Abstract
Abstract Iceberg calving, the process where icebergs detach from glaciers, remains poorly understood. Moreover, few parameterizations of the calving process can easily be integrated into numerical models to accurately capture observations, resulting in large uncertainties in projected sea level rise. Recent efforts have focused on estimating crevasse depths assuming tensile failure occurs when crevasses fully penetrate the glacier thickness. However, these approaches often ignore the role of advecting crevasses on calculations of crevasse depth. Here, we examine a more general crevasse depth calving model that includes crevasse advection. We apply this model to idealized prograde and retrograde bed geometries as well as a prograde geometry with a sill. Neglecting crevasse advection results in steady glacier advance and ice tongue formation for all ice temperatures, sliding law coefficients and constant slope bed geometries considered. In contrast, crevasse advection suppresses ice tongue formation and increases calving rates, leading to glacier retreat. Furthermore, crevasse advection allows a grounded calving front to stabilize on top of sills. These results suggest that crevasse advection can radically alter calving rates and hint that future parameterizations of fracture and failure need to more carefully consider the lifecycle of crevasses and the role this plays in the calving process.
Highlights
Calving is one of the largest sources of uncertainty in projected mass loss from ice sheets and glaciers (Stocker and others, 2013; Pörtner and others, 2019; Pattyn and Morlighem, 2020) and developing better models of the calving process is essential for accurate sea level projections
We first examined the effect of crevasse advection on terminus position using a prograde bed without a sill and varying ice temperature and sliding coefficient
With crevasse advection (Fig. 3b), basal crevasses that initiate before the grounding line advect past the grounding line, resulting in a crevassed region that penetrates the entire thickness 300 m from the calving front
Summary
Calving is one of the largest sources of uncertainty in projected mass loss from ice sheets and glaciers (Stocker and others, 2013; Pörtner and others, 2019; Pattyn and Morlighem, 2020) and developing better models of the calving process is essential for accurate sea level projections. The Nye zero stress criterion provides a simple method to introduce a physically motivated parameterization of calving into glacier models (Nye, 1957; Nick and others, 2010; Todd and Christoffersen, 2014; Ma and others, 2017; Ma and Bassis, 2019). This criterion assumes crevasses penetrate to the depth in the glacier where the largest effective principle stress vanishes. The method is computationally cheap to incorporate into models and straightforward to implement compared to other theories that can be cumbersome to include in ice-sheet models, such as linear elastic fracture mechanics (Krug and others, 2014; Yu and others, 2017; Jiménez and Duddu, 2018)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
