Temporal englacial water content variability associated with a rapidly retreating glacier

This study uses a combination of evidence from ground penetrating radar, borehole, video, and wireless probe data to assess temporal changes in englacial water content associated with Briksdalsbreen, a rapidly retreating Norwegian glacier. Over a 13 day period in 2006, ice radar-wave velocity varied between 0.135 m/ns (+/- 0.009) and 0.159 m/ns (+/- 0.003), and water content from 7.8% (+2.6, -2.8) to 2.5% (+0.9, -1.1) [derived from the Looyenga (Physica 31(3): 401-406, 1965) formula]. It is suggested that during warm precipitation free days, void spaces within the glacier become filled with water, resulting in low radar-wave velocity. This stored water then drained during cold, high precipitation days, allowing the radar-wave velocity to rise. These changes in englacial storage were caused by the enhanced crevassing generated by the newly floating ice margin, and were associated with accelerated glacier retreat. Copyright (C) 2011 John Wiley & Sons, Ltd.