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Rapid dynamic activation of a marine-based Arctic ice cap


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Authors

McMillan, M 
Shepherd, A 
Gourmelen, N 
Dehecq, A 
Leeson, A 

Abstract

jats:titleAbstract</jats:title>jats:pWe 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 (~ 10jats:sup1</jats:sup> m/yr) to fast (~ 10jats:sup3</jats:sup> 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.</jats:p>

Description

Keywords

Altimetry, Austfonna, Dynamic instability, Ice cap, InSAR, Mass balance

Journal Title

Geophysical Research Letters

Conference Name

Journal ISSN

0094-8276
1944-8007

Volume Title

41

Publisher

Blackwell Publishing Ltd
Sponsorship
This work was supported by the UK Natural Environment Research Council.