Sensitivity of centennial mass loss projections of the Amundsen basin to the friction law

• Published in: The Cryosphere
• Main Authors: Brondex, Julien, Gillet-Chaulet, Fabien, GAGLIARDINI, Olivier
• Other Authors: Institut des Géosciences de l’Environnement (IGE), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Recherche pour le Développement (IRD)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 )
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: [SDE]Environmental Sciences; Amundsen Sea; Weertman; amundsen basin; The Cryosphere
• Online Access: https://hal.archives-ouvertes.fr/hal-03031516; https://hal.archives-ouvertes.fr/hal-03031516/document; https://hal.archives-ouvertes.fr/hal-03031516/file/Brondex%20et%20al.%20-%202019%20-%20Sensitivity%20of%20centennial%20mass%20loss%20projections%20of.pdf; https://doi.org/10.5194/tc-13-177-2019

International audience Reliable projections of ice sheets' future contributions to sea-level rise require models that are able to accurately simulate grounding-line dynamics, starting from initial states consistent with observations. Here, we simulate the centennial evolution of the Amundsen Sea Embayment in response to a prescribed perturbation in order to assess the sensitivity of mass loss projections to the chosen friction law, depending on the initialisation strategy. To this end, three different model states are constructed by inferring both the initial basal shear stress and viscosity fields with various relative weights. Then, starting from each of these model states, prognostic simulations are carried out using a Weertman, a Schoof and a Budd friction law, with different parameter values. Although the sensitivity of projections to the chosen friction law tends to decrease when more weight is put on viscosity during initialisation, it remains significant for the most physically acceptable of the constructed model states. Independently of the considered model state, the Weertman law systematically predicts the lowest mass losses. In addition, because of its particular dependence on effective pressure, the Budd friction law induces significantly different grounding-line retreat patterns than the other laws and predicts significantly higher mass losses.