Constraining an Ocean Model Under Getz Ice Shelf, Antarctica, Using A Gravity‐Derived Bathymetry

• Published in: Geophysical Research Letters
• Main Authors: Millan, Romain, St‐laurent, Pierre, Rignot, Eric, Morlighem, Mathieu, Mouginot, Jeremie, Scheuchl, Bernd
• 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)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: [SDE]Environmental Sciences; Antarc*; Antarctica; Berry Glacier; Getz Ice Shelf; Ice Shelf
• Online Access: https://hal.science/hal-03026251; https://hal.science/hal-03026251/document; https://hal.science/hal-03026251/file/2019GL086522.pdf; https://doi.org/10.1029/2019GL086522

International audience Getz Ice Shelf, the largest producer of ice shelf meltwater in Antarctica, buttresses glaciers that hold enough ice to raise sea level by 22 cm. We present a new bathymetry of its sub‐ice shelf cavity using a three‐dimensional inversion of airborne gravity data constrained by multibeam bathymetry at sea and a reconstruction of the bedrock from mass conservation on land. The new bathymetry is deeper than previously estimated with differences exceeding 500 m in a number of regions. When incorporated into an ocean model, it yields a better description of the spatial distribution of ice shelf melt, specifically along glacier grounding lines. While the melt intensity is overestimated because of a positive bias in ocean thermal forcing, the study reveals the main pathways along which warm oceanic water enters the cavity and corroborates the observed rapid retreat of Berry Glacier along a deep channel with a retrograde bed slope.