Dye-tracer studies of the hydrology of a High Arctic polythermal valley glacier: implications for glacier motion

RG Bingham, PW Nienow, MJ Sharp, S Boon, KE Heppenstall

Research output: Chapter in Book/Report/Conference proceedingConference Contribution (Conference Proceeding)

Abstract

It is well recognised that the passage of water through temperate glaciers impacts significantly upon their pattern of ice dynamics. By contrast, the impact of subglacial hydrology on the dynamics of polythermal glaciers is poorly understood, due in part to a dearth of relevant data. During summer 2000, field investigations were undertaken at John Evans Glacier, a polythermal glacier on Ellesmere Island (79°40'N, 79°00'W), to: i) characterise the subglacial hydrology of the glacier and determine the extent to which it evolved over the course of a melt season; and ii) establish whether variations in subglacial hydrology affected rates of glacier motion. Known quantities of fluorescent dye were injected periodically into the englacial system via moulins, and dye emergence was detected in a single stream emerging from the terminus 5km downglacier. Dye tests in late June generated highly dispersed breakthrough curves and low mean flow velocities (~ 0.14 ms-1) indicative of inefficient distributed drainage conditions. By early August, dye transit velocities between the same nodes were fast (~ 0.7 ms-1) and dye experienced little dispersion, indicating that the subglacial drainage had evolved into an efficient channelised system. Surface glacier motion was measured throughout the summer season using standard surveying and differential GPS techniques to monitor a network of stakes across the glacier surface. Highest horizontal velocities were observed in late June throughout the lower glacier in conjunction with uplift at a number of stakes. We hypothesise that the surface motion variations are directly related to the seasonal evolution of the subglacial drainage system. The role of hydrology on ice dynamics in polar regions may, under certain conditions, be very similar to that recognised from temperate glaciers.
Translated title of the contributionDye-tracer studies of the hydrology of a High Arctic polythermal valley glacier: implications for glacier motion
Original languageEnglish
Title of host publicationCanadian Geophysical Union/Eastern Snow Conference Joint Meeting, Ottawa, ON, Canada
Publication statusPublished - 2001

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