Impact of Subglacial Freshwater Discharge on Pine Island Ice Shelf

Satellite-based estimates of ice shelf melt rates reach similar to 200 m yr-1 close to the grounding line of Pine Island Glacier, in West Antarctica. However, ocean simulations have not yet been able to reproduce such high melt rates, even with high-resolution models. Here, we use a regional model of Pine Island ice shelf cavity and study the impact of subglacial freshwater discharge on simulated ice shelf melt rates and ocean circulation in the cavity. We show that subglacial freshwater discharge substantially enhances ice shelf melting close to the grounding line, successfully simulating high ice shelf melt rates suggested by observations. The buoyant mixture of glacial meltwater plume rises to similar to 27.4 isopycnal surfaces, following topographically constrained current, and spreads into mid-depths at the ice shelf front. The role of freshwater discharge is likely to remain unchanged over the coming decades given the projected evolution of runoff and rainfall over Pine Island basin.

Automated summary

The study shows that subglacial freshwater discharge significantly increases ice shelf melting rates, successfully simulating the high ice shelf melt rates suggested by observations. The buoyant mixture of glacial meltwater plume rises and spreads forward, affecting ocean circulation.