Surge dynamics on Bering Glacier, Alaska, in 2008–2011 1Department of Geography, University of Utah, Salt Lake City, Utah, USA
07 Nov 2012
2Geophysical Institute, University of Alaska Fairbanks, Fairbanks, Alaska, USA
3Department of Geography, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany
Received: 21 February 2012 – Published in The Cryosphere Discuss.: 21 March 2012 Abstract. A surge cycle of the Bering Glacier system, Alaska, is examined using
observations of surface velocity obtained using synthetic aperture radar
(SAR) offset tracking, and elevation data obtained from the University of
Alaska Fairbanks LiDAR altimetry program. After 13 yr of quiescence, the
Bering Glacier system began to surge in May 2008 and had two stages of
accelerated flow. During the first stage, flow accelerated progressively for
at least 10 months and reached peak observed velocities of ~ 7 m d−1.
The second stage likely began in 2010. By 2011 velocities
exceeded 9 m d−1 or ~ 18 times quiescent velocities. Fast
flow continued into July 2011. Surface morphology indicated slowing by fall
2011; however, it is not entirely clear if the surge is yet over.
Revised: 10 October 2012 – Accepted: 12 October 2012 – Published: 07 November 2012
The quiescent phase was characterized by small-scale acceleration events
that increased driving stresses up to 70%. When the surge initiated,
synchronous acceleration occurred throughout much of the glacier length.
Results suggest that downstream propagation of the surge is closely linked
to the evolution of the driving stress during the surge, because driving
stress appears to be tied to the amount of resistive stress provided by the
bed. In contrast, upstream acceleration and upstream surge propagation is not
dependent on driving stress evolution.
Citation: Burgess, E. W., Forster, R. R., Larsen, C. F., and Braun, M.: Surge dynamics on Bering Glacier, Alaska, in 2008–2011, The Cryosphere, 6, 1251-1262, doi:10.5194/tc-6-1251-2012, 2012.