Abstract

Ice loss from the West Antarctic Ice Sheet is a significant contributor to sea-level rise. The ice loss is thought to have been triggered by fluctuations in the delivery of oceanic heat to the base of ice shelves. However, the response of ice sheets to ocean variability remains poorly understood. Applying a novel synchronously coupled ice-ocean model, this study considers the response of an ice sheet to periodic variations in ocean forcing. The results show that the amplitude of oscillations in grounded ice volume grow as a non-linear function of ocean forcing period. This implies that slower oscillations in climatic forcing are disproportionately important to ice sheets. The residence time of ice shelves offers a critical time scale, above (below) which the ice response amplitude is a linear (quadratic) function of ocean forcing period. These results highlight the sensitivity of West Antarctic ice streams to perturbations in heat fluxes occurring at interannual and decadal time scales.