Sensitivity of grounding line dynamics to the choice of the friction law

• Published in: Journal of Glaciology
• Main Authors: Brondex, Julien, Gagliardini, Olivier, Gillet-Chaulet, Fabien, Durand, Gaël
• Other Authors: Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 )
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: glacier mechanics; glacier modelling; ice-sheet modelling; subglacial processes; [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; [PHYS.MECA]Physics [physics]/Mechanics [physics]; [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; Greenland; Weertman; Antarc*; Antarctica; glacier; Ice Sheet; Journal of Glaciology
• Online Access: https://hal.science/hal-04693941; https://hal.science/hal-04693941/document; https://hal.science/hal-04693941/file/sensitivity-of-grounding-line-dynamics-to-the-choice-of-the-friction-law.pdf; https://doi.org/10.1017/jog.2017.51

International audience Basal slip accounts for a large part of the flow of ice streams draining ice from Antarctica and Greenland into the ocean. Therefore, an appropriate representation of basal slip in ice flow models is a prerequisite for accurate sea level rise projections. Various friction laws have been proposed to describe basal slip in models. Here, we compare the influence on grounding line (GL) dynamics of four friction laws: the traditional Weertman law and three effective pressure-dependent laws, namely the Schoof, Tsai and Budd laws. It turns out that, even when they are tuned to a common initial reference state, the Weertman, Budd and Schoof laws lead to thoroughly different steady-state positions, although the Schoof and Tsai laws lead to much the same result. In particular, under certain circumstances, it is possible to obtain a steady GL located on a reverse slope area using the Weertman law. Furthermore, the predicted transient evolution of the GL as well as the projected contributions to sea level rise over a 100-year time horizon vary significantly depending on the friction law. We conclude on the importance of choosing an appropriate law for reliable sea level rise projections and emphasise the need for a coupling between ice flow models and physically based subglacial hydrological models.