Do eddies connect the tropical Atlantic Ocean and the Gulf of Mexico?

TL;DR

This study uses geodesic eddy detection to show that North Brazil Currents Rings do not effectively transport material across the Lesser Antilles into the Caribbean or Gulf of Mexico, challenging previous Eulerian assessments.

Contribution

The paper demonstrates that Eulerian eddy detection methods are inadequate and introduces geodesic eddy detection as a more accurate approach for tracking eddy coherence and material transport.

Findings

North Brazil Currents Rings are not coherent enough to bypass the Lesser Antilles.

Eddy filamentation leads to loss of coherence before reaching the Caribbean.

Material from NBCRs does not significantly penetrate into the Caribbean Sea or Gulf of Mexico.

Abstract

Consistent with satellite-tracked trajectories of drogued drifters, but at odds with Eulerian assessment of satellite-altimetry measurements of sea-surface height, we show that North Brazil Currents Rings (NBCRs) are incapable of bypassing the Lesser Antilles as structures that coherently transport material. The nature of the inability of the de-facto oceanographic Eulerian, streamline-based eddy detection technique to produce a correct assessment is rooted in its lack of objectivity. We arrive at this conclusion by applying \emph{geodesic eddy detection} on the altimetric dataset over nearly its entire extent. While we detect northwestward translating NBCRs that can be classified as coherent Lagrangian eddies, they typically experience strong filamentation and complete loss of coherence prior to reaching the Lesser Antilles. Moreover, the filamented material hardly penetrates into the Caribbean Sea, let alone the Gulf of Mexico, and not without substantively mixing with the ambient fluid east of the archipelago.