Dynamics of Subglacial Plumes and Seawater Intrusion at the Ice-Ocean Interface

Accurate quantification of melt rates of marine-terminating glaciers is one of the most critical challenges in contemporary glaciology (Straneo & Cenedese, 2015), where small-scale ice-ocean interactions play an important role (Mamer et al., 2024). However, large-scale coupled models often misrepresent the processes that mediate these interactions, which increases uncertainty in future projections. These systems discharge substantial volumes of cold freshwater into the open ocean through subglacial plumes. The dynamics of these buoyant plumes are crucial for heat transfer, mixing, and melting processes at the ice-ocean boundary.  Previous studies have demonstrated that, under specific conditions influenced by discharge, system density, and ambient turbulence, seawater may enter the subglacial cavity as a wedge-shaped density front (Wilson et al., 2020). The mechanisms that promote or inhibit seawater intrusion and mixing remain poorly understood. To address this, we carried out direct numerical simulations (DNS) of a subglacial channel discharging into the open ocean, following the laboratory experiments of Wilson et al. (2020), and evaluated the impact of different densimetric Froude numbers on seawater intrusion and the resulting buoyant plume. Our findings provide new insights into the role of subglacial plumes in heat and salt transport, thereby clarifying the mechanisms that drive melting at the ice-ocean interface.