Rapid dynamic activation of a marine-based Arctic ice cap

• Published in: Geophysical Research Letters
• Main Authors: Mcmillan, Malcolm, Shepherd, Andrew, Gourmelen, Noel, Dehecq, Amaury, Leeson, Amber, Ridout, Andrew, Flament, Thomas, Gilbert, Lin, Benham, Toby, van den Broeke, Michiel, Dowdeswell, J.A., Fettweis, Xavier, Noël, Brice, Strozzi, T.
• Other Authors: University of Leeds, Centre for Polar Observation and Modelling (CPOM), Natural Environment Research Council (NERC), School of Geosciences Edinburgh, University of Edinburgh (Edin.), Laboratoire d'Informatique, Systèmes, Traitement de l'Information et de la Connaissance (LISTIC), Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry ), Scott Polar Research Institute, University of Cambridge UK (CAM), Institute for Marine and Atmospheric Research Utrecht (IMAU), Universiteit Utrecht / Utrecht University Utrecht, Département de Géographie, Université de Liège, Gamma Remote Sensing and Consulting AG, Gamma Remote Sensing Research and Consulting AG
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2014
• Subjects: [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; Arctic; Austfonna; Ice cap
• Online Access: https://hal.science/hal-01102899; https://hal.science/hal-01102899/document; https://hal.science/hal-01102899/file/McMillan_et_al_2014_Geophysical_Research_Letters.pdf; https://doi.org/10.1002/2014GL062255

International audience We use satellite observations to document rapid acceleration and ice loss from a formerly slow-flowing, marine-based sector of Austfonna, the largest ice cap in the Eurasian Arctic. During the past two decades, the sector ice discharge has increased 45-fold, the velocity regime has switched from predominantly slow (~ 101 m/yr) to fast (~ 103 m/yr) flow, and rates of ice thinning have exceeded 25 m/yr. At the time of widespread dynamic activation, parts of the terminus may have been near floatation. Subsequently, the imbalance has propagated 50 km inland to within 8 km of the ice cap summit. Our observations demonstrate the ability of slow-flowing ice to mobilize and quickly transmit the dynamic imbalance inland; a process that we show has initiated rapid ice loss to the ocean and redistribution of ice mass to locations more susceptible to melt, yet which remains poorly understood.