arXiv subjects

Alex P. Encinas Bartos

Publications and source records attributed to Alex P. Encinas Bartos.

2 recordsLinked to original sources

arXiv2022

Quasi-Objective Eddy Visualization from Sparse Drifter Data

We employ a recently developed single-trajectory Lagrangian diagnostic tool, the trajectory rotation average $ (\mathrm{\overline{TRA}}) $, to visualize oceanic vortices (or eddies) from sparse drifter data. We apply the $ \mathrm{\overline{TRA}} $ to two drifter data sets that cover various oceanographic scales: the Grand Lagrangian Deployment (GLAD) and the Global Drifter Program (GDP). Based on the $ \mathrm{\overline{TRA}} $, we develop a general algorithm that extracts approximate eddy boundaries. We find that the $ \mathrm{\overline{TRA}} $ outperforms other available single-trajectory-based eddy detection methodologies on sparse drifter data and identifies eddies on scales that are unresolved by satellite-altimetry.

physics.flu-dyn↗

arXiv2022

Quasi-Objective Coherent Structure Diagnostics from Single Trajectories

We derive measures of local material stretching and rotation that are computable from individual trajectories without reliance on other trajectories or on an underlying velocity field. Both measures are quasi-objective: they approximate objective (i.e., observer-independent) coherence diagnostics in frames satisfying a certain condition. This condition requires the trajectory accelerations to dominate the angular acceleration induced by the spatial mean vorticity. We illustrate in examples how quasi-objective coherence diagnostics highlight elliptic and hyperbolic Lagrangian coherent structures even from very sparse trajectory data.

physics.flu-dyn↗