Controls on the flow configuration of Vanderford Glacier, East Antarctica

Vanderford Glacier is one of the fastest retreating glaciers in East Antarctica, with approximately 18.6 km of grounding line retreat since 1996. Together with the Totten Glacier, the Vanderford Glacier is a key outlet glacier of the Aurora Subglacial Basin (ASB), which contains approximately 7 m of global sea level equivalent, of which ~3.5 m is vulnerable to ocean driven melting, and is rapidly losing mass. While the Totten Glacier currently discharges almost twice as much ice as the Vanderford Glacier, sediment records from the Sabrina and Knox Coast Sectors indicate that the Vanderford Glacier has had sedimentation rates over twice that at Totten in the past. Here, we examine the current flow configuration between Vanderford and Totten Glaciers and drivers of it, including interactions between the subglacial topography, hydraulic potential, climate, and ice sheet dynamics. We use the Ice-sheet and Sea-level System Model (ISSM) under experiments of heightened ocean warming concentrated at Vanderford Glacier, and heightened surface mass balance at Totten Glacier, to show that the present-day flow configuration between the Totten and Vanderford Glaciers is tenuous. Rerouting towards Vanderford Glacier could occur under even minor changes in surface elevation at both glaciers. Such rerouting potentially exposes large parts of the underbelly of the ASB to enhanced ocean-driven ice shelf melting in the event of rapid retreat of Vanderford Glacier, with implications for global sea level rise.