Ice-Shelf Resonance Deflections Modelled with a 2D Elastic Centre-Line Model

Abstract

Ice-shelf flexure modelling was performed using a 2D finite-difference elastic model, which takes into account sub-ice-shelf seawater flux. The sub-ice seawater flux was described by the continuity equation linked with the linear Euler equation. In the model ice shelf flexures result from variations in the incoming (outgoing) sea water flux, which flows into (out of) the sub-ice-shelf channel. The numerical experiments were carried out for the centre line, which passes from the summit to the glacier terminus along one of the fastest ice-stream at the Academy of Sciences Ice Cap. The profile includes a part of the adjacent ice-shelf. The numerical experiments were carried out for harmonic incoming seawater fluxes and the ice-shelf flexures were obtained for a wide spectrum of the seawater flux frequencies, ranging from tidal periods down to periods of a few tens of seconds (0.001..0.06 Hz). The solutions obtained by the model are in agreement (in amplitude of the flexures) with the ones obtained by the model of Holdsworth and Glynn (1978). The amplitudes of modelled ice-shelf deflections reach a maxima and it's in concordance with previous investigations of the impact of ocean waves on Antarctic ice shelves [1]. The explanation of the effect is found in the existence of a resonance at these high frequencies.