Mesoscale Eddies in the Brazilian Continental Margin

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The South Atlantic is unique in that it transports heat equatorward instead of poleward, and recent studies suggest that the South Atlantic meridional overturning circulation (MOC) undergoes strong short-term variability, likely due to mesoscale eddies. Nevertheless, the Brazilian continental margin, upstream of the Brazil-Malvinas Confluence, lacks an in-depth characterization of mesoscale eddies. This project will develop a detailed characterization of the structure and variability of eddies in this region using a synergistic observational approach. The project will inform efforts to model carbon sequestration and redistribution, which requires an accurate representation of mesoscale eddies, by providing an observational benchmark. It will support an early career PI and broaden the physical oceanography curriculum at the University of Connecticut (UConn). A doctoral student will be trained, and the PI and graduate student will share the science of ocean eddies with high schoolers in the UConn Pre-College Summer Program.The project aims to characterize the synoptic horizontal and vertical structure of eddies, build eddy composites and estimate their anomalous heat and salt/freshwater contents, for the Brazilian continental margin region between about 20 to 35 degrees S. Data from altimetric products (along-track and mapped absolute dynamic topography and sea-level anomalies as well as eddy-tracking trajectories), Argo floats (profiles and trajectories), and high-resolution XBT/CTD transects will be used. These approaches will be utilized to differentiate between local and remote eddies in the Brazil Current region, test the hypothesis that remote eddies contribute significantly to the mesoscale variability in the Brazil Current region, and produce a detailed look into the mesoscale variability of the Brazilian continental margin. Specifically, the project will (a) characterize the statistics of eddy characteristics and their seasonal and interannual variability, (b) study in detail representative individual eddies, (c) build two-dimensional and three-dimensional eddy composites and (d) quantify the anomalous heat and salt/freshwater content of eddies.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.