Rodrigo Duran, Planetary Science Institute: Loop Current Eddy Separations

Описание: COMPASS 2025-10-24: Rodrigo Duran, Planetary Science Institute
"On the Physical Mechanisms Controlling Loop Current Eddy Separations and Their Seasonality"

The Loop Current (LC) and its eddy-shedding dynamics profoundly impact the Gulf of Mexico, influencing hurricane intensity, offshore platform safety, algal blooms, and the fishing industry. However, the driving mechanisms behind the well-documented seasonality of eddy-shedding events have remained a long-standing open question. This study resolves that question by shifting from a descriptive kinematic view to a causal energetic framework. This breakthrough is achieved through the combination of three complementary methodologies: canonical energy transfers to reproducibly quantify key instabilities, information-flow theory to independently confirm causality, and vorticity transport barriers from nonlinear dynamical systems theory to explain the permanent separation mechanism. Using 30 years of altimetry data and a 22-year reanalysis, we trace a direct causal chain: The summer seasonal maximum in mean kinetic energy of the Yucatan Current drives intense cyclonic vorticity production via barotropic instability. This vorticity leads to LC frontal eddies that cut through the LC, and the formation of a vorticity transport barrier causing the separation to become final as it dynamically severs the new eddy from the main current. The rarity of December shedding events arises from the combined effects of reduced vorticity production and strong wind-driven damping of eddies. This framework reveals that the separation mechanism exists year-round, with seasonality emerging from the modulation of energy pathways, providing a theoretical foundation for LC dynamics and a physical basis for predicting critical events related to tropical cyclone intensification and offshore platform safety.