Drivers and Reversibility of Abrupt Ocean State Transitions in the Amundsen Sea, Antarctica

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Caillet, Justine, Jourdain, Nicolas, C, Mathiot, Pierre, Hellmer, Hartmut, H, Mouginot, Jérémie
• Other Authors: Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (Fédération OSUG)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP), Université Grenoble Alpes (UGA), Institut de gestion des entreprises -USJ (IGE), Université Saint-Joseph de Beyrouth (USJ), Alfred Wegener Institute for Polar and Marine Research (AWI), ANR-19-CE01-0015,EIS,Elmer/Ice-Sheet : un modèle dédié à l'étude des changements rapides de calottes polaires(2019), European Project: 820575,TiPACCs
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; Amundsen Sea; Antarctic; Misi; Pine Island Glacier; West Antarctic Ice Sheet; Antarc*; Ice Sheet; Ice Shelf; Ice Shelves; Pine Island
• Online Access: https://hal.science/hal-04301354; https://hal.science/hal-04301354v1/document; https://hal.science/hal-04301354v1/file/caillet_JGR_2023.pdf; https://doi.org/10.1029/2022jc018929

International audience The West Antarctic Ice Sheet has lost mass over the last few decades and has thus contributed significantly to global sea level rise. Warming of the oceanic sub-surface seems to have caused an increase in melting under floating ice shelves, particularly in the Amundsen Sea (Jenkins et al., 2018). Depending on the bedrock slope direction (Pattyn et al., 2012; Schoof, 2007) and ice-shelf lateral buttressing (Gudmundsson, 2013), a sufficiently strong and persistent increase in basal melting can lead to a marine ice-sheet instability (MISI), resulting in a self-sustained retreat of the glacier's grounding line and to the acceleration of its flow (Favier et al., 2014; Joughin et al., 2014). Instabilities are triggered above a certain level of ocean warming (critical threshold or tipping point), with the possible existence of multiple thresholds. Thus, Rosier et al. (2021) estimated that Pine Island Glacier would undergo a MISI and major mass loss for an oceanic warming of +1.2°C relative to the present. Garbe et al. (2020) estimated that a tipping point of +2°C global warming relative to preindustrial could cause a MISI of the entire