Mesoscale eddies play a key role in material exchange between the Antarctic continental shelf and the open ocean, yet their seasonal variability and energetic mechanisms remain poorly understood. Here we use a 1.5 km resolution Ross Sea ocean–sea ice–ice shelf coupled model (ROSIM_v1.5km) to investigate the seasonal cycle and energy budget of eddy kinetic energy (EKE) over the Ross Sea continental shelf.

EKE exhibits pronounced seasonality, reaching a maximum in March under strong surface forcing and decreasing to a minimum in July as sea ice expands. Meanwhile, baroclinic energy conversion increases progressively in response to sea-ice–induced brine rejection and enhanced stratification, reaching a maximum in September and then weakening thereafter, indicating a transition from a surface-forced to a baroclinic-dominated EKE regime. In contrast, the polynya region shows a delayed EKE maximum in September, associated with persistent deep convection and sustained baroclinic instability.

Vertically, EKE is intensified in both the surface and bottom boundary layers, while interior EKE is primarily maintained by baroclinic conversion. EKE budget analysis shows that dissipation dominates, together with lateral advective and pressure-work fluxes across the shelf and conversion from EKE to mean flow, indicating strong local damping of eddy and limited offshore export.

These results demonstrate that Ross Sea EKE is governed by a seasonally evolving transition between surface-generated and baroclinic energy pathways, controlled by sea-ice cover and stratification. Under a changing Southern Ocean climate, projected variations in sea-ice cover and formation processes may therefore substantially modify EKE and cross-shelf exchange of heat and freshwater.