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Three stations near the calving front of the Ross Ice Shelf, Antarctica, recorded GPS data through a full spring-neap tidal cycle in November 2005. The data revealed a diurnal horizontal motion that varied both along and transverse to the long-term average velocity direction, similar to tidal signals observed in other ice shelves and ice streams. Based on its periodicity, it was hypothesized that the signal represents a flow response of the Ross Ice Shelf to the diurnal tides of the Ross Sea. To assess the influence of the tide on the ice-shelf motion, two hypotheses were developed. The first addressed the direct response of the ice shelf to tidal forcing, such as forces due to sea-surface slopes or forces due to sub-ice-shelf currents. The second involved the indirect response of ice-shelf flow to the tidal signals observed in the ice streams that source the ice shelf. A finite-element model, based on viscous creep flow, was developed to test these hypotheses, but succeeded only in falsifying both hypotheses, i.e. showing that direct tidal effects produce too small a response, and indirect tidal effects produce a response that is not smooth in time. This nullification suggests that a combination of viscous and elastic deformation is required to explain the observations. [ABSTRACT FROM AUTHOR]

The article discusses the study which examines the vertical motions of the large tidally modulated flow that interact with the ice streams feeding the Ross Ice Shelf in Antarctica. It states that the flow of the Ross Ice Shelf front ice streams exhibits smooth and sinusoidal motions corresponding to tidal modulation. It notes that the possible linking of the ice shelf with the ice streams to form a unified system has responded to small perturbations in stresses associated with ocean tides. It confirms the presence of the sinusoidal motion and damping of very high-frequency signals despite the absence of stick-slip motions.