Collaborative Research: Quantifying Real-World Ice-Ocean Interaction Physics with the Fidelity Required for Next-Generation Melt Prediction

Processes at the ice-ocean interface of marine-terminating glaciers play a critical role in determining the rate of ice sheet mass loss and the depth at which meltwater enters the ocean. Submarine melting along glacier ice faces, traditionally thought to be governed by the strength of subglacial discharge, also influences iceberg calving rates. However, emerging evidence reveals the presence of energetic dynamics elsewhere along the ice face, driving turbulent flows that remain poorly understood and underrepresented in existing models. These dynamics challenge current parameterizations of melt and freshwater flux, underscoring the need to directly validate and improve these frameworks. Specifically, there is the need to accurately represent their role in amplifying feedback loops and nudging the climate system toward potential tipping points relating to accelerated ice loss and disrupted ocean circulation. This project will integrate direct measurements of submarine melt rates and near-ice boundary-layer dynamics at Greenland’s marine-terminating glaciers with numerical simulations to improve the next-generation climate models. Beyond the importance to society and the scientific community, the work will provide mentorship and support for early career researchers, post docs, graduate and undergraduate students, and outreach with a local community as part of a conversation about their changing icy landscape. This proposal will support development of a robust, observationally grounded model for submarine melt prediction at Greenland glacier termini. Current melt parameterizations have largely been formulated for limiting cases where shear or convection dominates and assume simplified geometries and idealized ice and ocean forcing. The investigators recently developed instruments that directly measure the evolving ice boundary and demonstrated that melt is controlled by the interplay between fjord currents, turbulent eddies and near-boundary buoyancy that interact with a complex three-dimensional glacier-ice interface. Moreover, flow along the boundary were found to be significantly more energetic, with melt rates higher than predicted by current theory. This work hypothesizes that a skillful (unbiased) scale-aware melt parameterization will require an improved accounting for all sources of kinetic energy and how they drive the turbulent and diffusive ice-ocean boundary layer. Thus, the investigators propose a focused yet comprehensive set of small-scale measurements of submarine melt and the ice-ocean boundary layer across distinct turbulent regimes. These and larger-scale measurements will be integrated with a suite of numerical simulations to characterize submarine melt rates as functions of temperature, subglacial discharge, fjord dynamics, and other key factors, ultimately providing a framework generalizable to diverse glacier systems. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.