Hydro-sliding and the Springtime Dynamical Evolution of Kennicott Glacier, Alaska
Abstract
Glacier basal motion is a poorly understood aspect of glacier mechanics that is responsible for the majority of ice flux on fast-flowing glaciers, enables rapid changes in glacier motion, and provides the means by which glaciers shape alpine landscapes. We collect hydrometerologic data and GPS-derived ice surface motion to probe the link between subglacial water pressure and the evolution of glacier velocity on Kennicott Glacier, Alaska. We find a chaotic timeseries of >50 m fill-and-drain sequences on the well-connected ice-marginal Donoho Falls Lake. Glacier velocity in the down-glacier reach responds sensitively to lake stage, with high amplitude diurnal velocity fluctuations during high or rising stage. The timing of velocity peaks precedes peak stage by 2-3 hours, and synchronously shifts earlier in the day throughout our observation period. We find the up-glacier station appears to first speed up in response to longitudinal coupling with accelerating down-glacier ice before responding to local variations in basal traction. We find the transition to responding to local basal conditions results in the glacier behaving more uniformly, with similar magnitude diurnal velocity fluctuations, synchronous timing of velocity extrema across the 10 km study reach, and steadier longitudinal strain rates.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.C53D..01A
- Keywords:
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- 0720 Glaciers;
- CRYOSPHERE;
- 0746 Lakes;
- CRYOSPHERE;
- 0758 Remote sensing;
- CRYOSPHERE;
- 0762 Mass balance 0764 Energy balance;
- CRYOSPHERE