The Xiamen Symposium on Marine Environmental Sciences (XMAS 2025)

The eddy-mean flow interactions in the western boundary currents play an important role in the heat transport and energy distribution of the global ocean. However, few studies focus on the Brazil Current (BC) system. In this study, we analyzed the three-dimensional structure of the eddy-mean flow interactions and seasonal variability of kinetic energy and eddy kinetic energy in the Brazil Current. The energy reservoirs and energy conversion terms are greatest in the upper 500 m, decreasing with depth. Strong eddy kinetic energy is contained in the Brazil-Malvinas Confluence (BMC) and the offshore portion of the BC jet. Strong barotropic instabilities can be found at the surface, while the strongest baroclinic instabilities are located in the subsurface layer. The kinetic energy of the BC jet shows a weak seasonal cycle, with a minimum in winter. In the BMC region, the strongest eddy kinetic energy occurs in austral autumn. The barotropic conversion terms in the BC jet and the BMC region show a significant seasonal cycle in the upper 500 m. However, the maximum baroclinic conversion terms occur at around 200 m.

Western Boundary Current, seasonal variability, mesoscale processes