Off the coast of Patagonia lives the Malvinas Current, where the Antarctic Circumpolar Current churns through the narrow Drake Passage between Cape Horn and the South Shetland Islands. Beron-Vera et al. reveal the near-surface Lagrangian dynamics of this specific stretch of the South Atlantic.
Using deterministic and probabilistic tools from nonlinear dynamics, the researchers studied Lagrangian aspects of the current by examining the material strain and shear of its velocity field from satellite altimetry, and by monitoring the trajectories of satellite-tracked buoys in the region. The two approaches lead to results consistent with the analysis of in-situ data using infinite-dimensional dynamical systems tools.
The authors found the Malvinas Current sustains a Lagrangian-Eulerian stability duality, a surprising result due to the known tendency of laminar flows to produce chaotic fluid particle trajectories. Additionally, the current acts as a barrier between water from its east and west sides, inhibiting transport between the regions.
“This prevents mixing between Patagonian Shelf and open ocean waters, as well as constraining the connectivity for marine biota with limited swimming capacity,” said author Francisco Beron-Vera.
A key distinguishing property of the Malvinas Current observed by the work is the v-shaped chevron patterning within the fluid flow. Similar structures have been seen in the cloud distribution in the atmosphere of Jupiter.
“We believe that we have provided, for the first time, evidence of similar structures developing in the ocean,” said Beron-Vera.
Connections between Jupiter’s chevrons and inertial-gravity wave motions may inspire future work investigating the effects of internal waves on the Malvinas Current. According to the authors, studying these oceanic patterns can lead to a better understanding of weather dynamics in gas giants.
Source: “Stability of the malvinas current,” by F. J. Beron-Vera, N. Bodnariuk, M. Saraceno, M. J. Olascoaga, and C. Simionato, Chaos (2020). The article can be accessed at https://doi.org/10.1063/1.5129441.