Two maps of the study site and a graph.
Study site in Brazil-Malvinas Confluence. The temperature-salinity and turbulence microstructure observations were carried out at stations 1-10, shown as the black points in (a). The color in (a) shows topography. This region is known to host active mesoscale eddies between the Brazil Current and the Malvinas Current. Panel (b) shows kinetic energy of these mesoscale eddies computed using satellite sea surface height data. The mesoscale eddy stirring effects can be seen as the zigzag profile shown as the red curve in the temperature salinity diagram shown in (c), demonstrating the water mass exchanges along density surfaces across two currents, the Brazil Current and the Malvinas Current. Credit: Orúe-Echevarría et al. (2023), Figure 1
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Journal of Geophysical Research: Oceans 

The Brazil-Malvinas Confluence, where the warm salty southward Brazil Current meets the cold fresh northward Malvinas Current, is known as the hotspot of water mass transformation and exchange between the Antarctic and South Atlantic Oceans. Although previous studies pointed out that mesoscale eddies play an important role in water mass modifications, the importance of 0.001-1-meter scale turbulent mixing has been unclear.

Using observations of large-scale temperature-salinity distributions and 0.001-1-meter scale turbulence microstructures, Orúe-Echevarría et al. [2023] find that turbulent mixing, which can mix water vertically (across-density surfaces), plays an equally important role as that induced by lateral (along-density surfaces) stirring in transforming water masses in upper 500 meter depth. The same methods based on the theory can be used for the data with higher spatial resolutions to diagnose the relative importance between vertical mixing and lateral starring, that is still elusive in many different regions of the world ocean. 

Citation: Orúe-Echevarría, D., Naveira Garabato, A. C., Polzin, K. L., Forryan, A., & Pelegrí, J. L. (2023). Mixing and overturning across the Brazil-Malvinas Confluence. Journal of Geophysical Research: Oceans, 128, e2022JC018730.

—Takeyoshi Nagai, Editor, JGR: Oceans

Text © 2023. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.