Spatial and temporal variability of the Brazil current path: Diagnostics from satellite-derived altimetry and a global reanalysis product
Year: 2025
Type: article
Abstract: The Brazil Current (BC) exhibits significant spatial and temporal variability. The generation of meanders and eddies off Cabo de São Tomé (22°S) and Cabo Frio (24°S) is a long-recognized phenomenon, linked to baroclinic instability and topographic influences. Concurrently, the BC's transport displays considerable annual and interannual fluctuations, affecting its trajectory and cross-sectional attributes. This study examines the long-term spatial and temporal variations of the BC's frontal position and structure between 21°S and 28°S, in the south-southeast Brazilian coast, analyzing 28 years of altimetry and global reanalysis data. Our results indicate that the BC's width, depth, core velocity and position show varying degrees of sensitivity to transport changes based on latitude. The current path is more (less) influenced by topographic gradients north (south) of 24°S. At this point, the energy exchange between the mean flow and eddies correlate with increases in transport, leading to a rise in downstream eddy kinetic energy (EKE) two months later. The BC's intensification and pathway alteration are influenced by broader phenomena, such as the wind stress associated with coastal upwelling delayed by two months, and the El Niño (NINO3.4 index) with an eight-month lag. Rotated Empirical Orthogonal Function analysis at two cross-stream sites near Cabo Frio confirms that variations in the BC's strength and transport are key factors driving velocity variance, together with the growth of eddies via baroclinic instability and the propagation of continental shelf waves.
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,270
OpenAlex ID: W4408071962