Rapid dynamic activation of a marine-based Arctic ice cap

• Published in: Geophysical Research Letters
• Main Authors: McMillan, M, Shepherd, A, Gourmelen, N, Dehecq, A, Leeson, A, Ridout, A, Flament, T, Hogg, A, Gilbert, L, Benham, Toby J., van den Broeke, M, Dowdeswell, Julian A., Fettweis, Xavier, Noël, Brice, Strozzi, T
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 2014
• Subjects: mass balance; Austfonna; dynamic instability; Physical; chemical; mathematical & earth Sciences; Earth sciences & physical geography; Physique; chimie; mathématiques & sciences de la terre; Sciences de la terre & géographie physique; Arctic; Ice cap
• Online Access: https://orbi.uliege.be/handle/2268/178243; https://orbi.uliege.be/bitstream/2268/178243/1/McMillan_et_al-2014-Geophysical_Research_Letters.pdf; https://doi.org/10.1002/2014GL062255

peer reviewed 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.