The circum-Antarctic ice-shelves respond to a more positive Southern Annular Mode with regionally varied melting

• Published in: Communications Earth & Environment
• Main Authors: Verfaillie, Deborah, Pelletier, Charles, Goosse, Hugues, Jourdain, Nicolas, Bull, Christopher, Dalaiden, Quentin, Favier, Vincent, Fichefet, Thierry, Wille, Jonathan
• Other Authors: Earth and Life Institute - Environmental Sciences (ELIE), Université Catholique de Louvain = Catholic University of Louvain (UCL), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), 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)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), University of Northumbria at Newcastle United Kingdom
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; Antarctic; Pacific; Antarc*; Ice Shelf; Ice Shelves; Sea ice
• Online Access: https://hal.science/hal-03874417; https://hal.science/hal-03874417/document; https://hal.science/hal-03874417/file/verfaillie_ComEaEnv_2022.pdf; https://doi.org/10.1038/s43247-022-00458-x

International audience The Southern Hemisphere cryosphere has recently shown regionally-contrasted responses to climate change, in particular to the positive phases of the Southern Annular Mode. However, the understanding of the impacts of this mode on ice-shelf basal melt at a circum-Antarctic scale is still limited. Here, we performed idealized experiments with a pan-Antarctic regional ice-shelf cavity-resolving ocean-sea-ice model for different phases of the Southern Annular Mode. We show that positive phases lead to increased upwelling and subsurface ocean temperature and salinity close to ice shelves, while the opposite occurs for negative phases. A one-standard-deviation increase of the Southern Annular Mode leads to a net basal mass loss of 40 Gt yr −1 , with strong regional contrasts: increased ice-shelf basal melt in the Bellingshausen and Western Pacific sectors and the opposite response in the Amundsen sector. Estimates of 1000-1200 and 2090-2100 ice-shelf basal melt changes due to the Southern Annular Mode are −86.6 Gt yr −1 and 55.0 to 164.9 Gt yr −1 , respectively, compared to the present.