Wintertime Supraglacial Lake Drainage Cascade Triggers Large‐Scale Ice Flow Response in Greenland

• Published in: Geophysical Research Letters
• Main Authors: Maier, Nathan, Andersen, Jonas, Kvist, Mouginot, Jérémie, Gimbert, Florent, Gagliardini, Olivier
• 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)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), ANR-19-CE01-0011,SOSIce,Observations spatiales des calottes polaires : changements de masse entre 2013 et maintenant(2019), ANR-17-CE01-0008,SEISMORIV,Instrumentation sismologique des rivières: un nouveau moyen de quantifier le role des evenements climatiques extremes sur la dynamique des rivières(2017)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: [SDE]Environmental Sciences; Greenland
• Online Access: https://hal.science/hal-04303862; https://hal.science/hal-04303862/document; https://hal.science/hal-04303862/file/Maier2023.pdf; https://doi.org/10.1029/2022gl102251

International audience Abstract Surface melt forces summertime ice‐flow accelerations on glaciers and ice sheets. Here, we show that large meltwater‐forced accelerations also occur during wintertime in Greenland. We document supraglacial lakes (SGLs) draining in cascades at unusually high elevation, causing an expansive flow acceleration over a ∼5,200 km 2 region during winter. The three‐component interferometric surface velocity field and decomposition modeling reveal the underlying flood propagation with unprecedented detail as it traveled over 160 km from the drainage site to the margin, providing novel constraints on subglacial water pathways, drainage morphology, and links with basal sliding. The triggering SGLs continuously grew over 40 years and suddenly released decades of stored meltwater, demonstrating surface melting can impact dynamics well beyond melt production. We show these events are likely common and thus their cumulative impact on dynamics should be further evaluated.