A one‐dimensional model of ice shelf‐ocean interaction

TLDR

Oceanic circulation beneath Antarctic ice shelves is driven by thermohaline differences from mass and energy exchange at the ice‑ocean interface, producing dense saline waters that emerge as cooled, diluted Ice Shelf Water plumes. The study develops a simple one‑dimensional model treating the Ice Shelf Water plume as a turbulent gravity current initiated by fresh meltwater at the inland margin. The model simulates the plume’s evolution as it ascends along a specified ice shelf base geometry. Applied to Ronne Ice Shelf, the model shows that a 0.6 °C warming of underlying water would raise the mean melt rate from 0.6 m yr⁻¹ to 2.6 m yr⁻¹, causing significant ice shelf thinning and potentially major changes in open‑shelf ocean circulation.

Abstract

Large‐scale oceanic circulation beneath Antarctic ice shelves is driven by the thenmohaline differences which result from mass and energy exchange at the ice‐ocean interface. Dense, saline waters are drawn underneath the ice shelves and emerge, cooled and diluted, as plumes of Ice Shelf Water. A simple, one‐dimensional model of this process has been developed, in which the Ice Shelf Water plume is treated as a turbulent gravity current, initiated at the inland margin by a flow of fresh meltwater emerging from beneath the grounded ice. Subsequent evolution of the plume, as it ascends along an ice shelf base of specified geometry, can be simulated. The model has been applied to a flow line on Ronne Ice Shelf, Antarctica, to explain the observed distribution and rate of basal melting and freezing. Calculations indicate that the present mean melt rate of 0.6 m yr −1 would increase to 2.6 m yr −1 if the underlying water were to warm by 0.6°C. This would not only lead to significant thinning of the ice shelf but could also cause a profound change in ocean circulation on the open continental shelf.