Spatial Characteristics and Dynamic Mechanisms of the Antarctic Slope Current in the Ross Sea

Coupled with the Antarctic Slope Front (ASF), the Antarctic Slope Current (ASC) encircles Antarctica and has variable structures. Two types of the ASC/ASF have been identified in the Ross Sea. Yet, the spatial characteristics of the ASC/ASF have not been depicted in detail, and the transition zone between the two different types is still unclear. Using an eddy-permitting coupled regional ocean-sea ice-ice shelf model, we aim to investigate the spatial characteristics and energy sources of the ASC/ASF in the Ross Sea. Based on the simulated results, three distinct structures of the ASC/ASF have been identified in three regimes from east to west: (i) in Regime I, the ASC is characterized by a westward flow in the upper layer and an eastward countercurrent in the lower layer; (ii) in Regime II, the undercurrent of the ASC reverses to the west and features a bottom intensification; (iii) in Regime III, the ASC in the upper layer is eastward, and the westward undercurrent still occupies the lower layer. By analyzing the momentum budget of the ASC, we quantified the respective contributions of barotropic and baroclinic pressure terms in determining the structure of the ASC/ASF. Furthermore, by analyzing the Mean Kinetic Energy budget of the ASC, we found that the Mean Available Potential Energy plays an important role in converting energy to the Mean Kinetic Energy, indicating that the maintenance of the ASC is closely associated with the available potential energy released from the ASF.