The 1982/83 surge and antecedent quiescent phase of Variegated Glacier: revising the original dataset for application in flow line models

Abstract

ABSTRACTThe extensive dataset of Variegated Glacier's 1982/83 surge and antecedent quiescent phase is fragmentary and predominantly of flow line nature. Applying the raw centre line data in a flow line model to conduct research into the mechanism behind Variegated Glacier's surge behaviour inevitably entails problems. In this study, the incomplete dataset is extrapolated into the upper and lower parts of the glacier. Furthermore, the centre line data are adapted to account for differences between width-averaged and centre line surface mass balance and ice thickness change, inflow from tributaries, and changes in surface width over time. The modifications to the dataset are backed-up by observations and clear, plausible physical explanations. Moreover, the revised dataset meets the imposed constraints regarding ice volume flux, specific mass balance and net volume change. Hence, the final dataset is considered a satisfying revision that makes the dataset more valuable for future research. Subsequent application of the revised dataset corroborates the idea that glacier evolution during quiescence is basically the growth back towards steady state after the glacier was brought out of balance by the preceding surge.