Baroclinic submesoscale eddies in the Ross Ice Shelf cavity alter heat pathways to the ice base

The influence of baroclinic submesoscale eddies on basal melting beneath the Ross Ice Shelf remains poorly understood. We analyzed a 4. 5-year mooring record from the central cavity and identified seven eddy-like events from density, velocity, and thermohaline anomalies, with horizontal scales (~11 km) characteristic of submesoscale motions capable of enhancing vertical heat transport. However, most events had little effect on basal melt: a mid-depth layer of cold water intrusions ('interleaving') acted as a thermohaline barrier, trapping warm, salty anomalies near 600 dbar and preventing their transfer to the ice base. Melt rates therefore remained near zero. In contrast, one exceptional eddy maintained a coherent vertical structure that overcame the interleaving, allowing warm, salty water to reach the ice base and coinciding with melt rates near the maximum observed (0. 048 \, m\, a^-1). These results reveal a state-dependent eddy–interleaving mechanism with implications for Ross Ice Shelf stability under climate change.