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Episodic ice velocity fluctuations triggered by a subglacial flood in West Antarctica
Author(s) -
Siegfried Matthew R.,
Fricker Helen A.,
Carter Sasha P.,
Tulaczyk Slawek
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl067758
Subject(s) - geology , ice stream , ice sheet , antarctic sea ice , fast ice , cryosphere , ice shelf , antarctic ice sheet , drift ice , ice divide , glaciology , streams , sea ice , climatology , geomorphology , oceanography , tectonics , paleontology , volcanism , computer network , computer science
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.