Episodic ice velocity fluctuations triggered by a subglacial flood in West Antarctica. Issue 6 (16th March 2016)

• Record Type: Journal Article
• Authors: Siegfried, Matthew R.; Fricker, Helen A.; Carter, Sasha P.; Tulaczyk, Slawek
• Is Part Of: Geophysical research letters. Volume 43:Issue 6(2016)
• Page Start: 2640
• Page End: 2648
• Publication Date: 2016-03-16
• Subjects: Antarctica -- glaciology -- ice dynamics -- subglacial hydrology -- subglacial lakes -- ice sheet; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2016GL067758
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Height change anomalies in satellite altimeter data have been interpreted as the surface expressions of basal water moving into and out of subglacial lakes. These signals have been mapped throughout Antarctica on timescales of months to years, but only broad connections have been made between active lakes and ice dynamics. We present the first high‐frequency observations of ice velocity evolution due to a cascading subglacial lake drainage event, collected over 5 years (2010–2015) using Global Positioning System data on Whillans and Mercer ice streams, West Antarctica. We observed three episodic ice velocity changes over 2 years, where flow speed increased by up to 4%, as well as an 11 month disruption of the tidally modulated stick‐slip cycle that dominates regional ice motion. Our observations reveal that basal conditions of an Antarctic ice stream can rapidly evolve and drive a dynamic ice response on subannual timescales, which can bias observations used to infer long‐term ice sheet changes. Key Points: Our array of continuous GPS stations captured a 3 year Antarctic subglacial lake drainage event Drainage event caused three episodic ice stream accelerations and disrupted normal stick‐slip motion Complex interplay between hydrology and ice dynamics highlights importance of long, continuous observation