Tidal bending of glaciers: a linear viscoelastic approach

• Main Authors: Reeh, Niels, Christensen, Erik Lintz, Mayer, Christoph, Olesen, Ole B.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2003
• Subjects: Annals of Glaciology; glacier; Greenland; Nioghalvfjerdsfjorden
• Online Access: https://orbit.dtu.dk/en/publications/20971dc6-0090-403e-b3d4-03d49c79efbf

In theoretical treatments of tidal bending of floating glaciers, the glacier is usually modelled as an elastic beam with uniform thickness, resting on an elastic foundation. With a few exceptions, values of the elastic (Young's) modulus E of ice derived from tidal deflection records of floating glaciers are in the range 0.9-3 GPa. It has therefore been suggested that the elastic-beam model with a single value of E approximate to 1 GPa adequately describes tidal bending of glaciers.In contrast, laboratory experiments with ice give E =93 GPa, i.e. 3-10 times higher than the glacier-derived values. This suggests that ice creep may have a significant influence on tidal bending of glaciers. Moreover, detailed tidal-deflection and tilt data from Nioghalvfjerdsfjorden glacier, northeast Greenland, cannot be explained by elastic-beam theory. We present a theory of tidal bending of glaciers based on linear viscoelastic-beam theory. A four-element, linear viscoelastic model for glacier ice with a reasonable choice of model parameters can explain the observed tidal flexure data. Implications of the viscoelastic response of glaciers to tidal forcing are discussed briefly.