Detection and Characterization of Mesoscale Eddies in the Gulf of California Using High-Resolution Satellite Altimetry

Mesoscale eddies play a key role in oceanic transport, but their characterization in marginal seas like the Gulf of California remains challenging due to complex coastlines and bathymetry that hinder conventional detection methods. This study addresses this gap by presenting a robust hybrid framework—integrating dynamical (Okubo-Weiss), velocity-geometry (Nencioli), and closed-contour (Chelton) criteria—applied to the high-resolution (0.01$^\circ$) Neural Ocean Surface Topography (NeurOST) altimetry product (2010–2024). Temporal continuity is ensured through a cost-based tracking algorithm optimized to tolerate observational gaps and track quasi-stationary features. This census, representing the first systematic, high-resolution sea surface height anomaly (SSHA)-based characterization for this region, identified 344 persistent trajectories ($\ge 14$ days) and revealed a fundamental dichotomy in the Gulf's dynamics: a transient, tidally-dominated regime in the north (dominated by short-lived features) contrasting sharply with a persistent, topographically-trapped regime in the south. Focusing on the long-lived population (lifetimes $> 30$ days), our analysis confirms that multi-year, quasi-stationary cyclonic eddies are trapped in the southern basins. Cyclonic structures dominate the Top 10 longest-lived tracks (90\%) and include two events with lifetimes confirmed to exceed 500 days. We also identify a robust seasonal decoupling between SSHA and sea surface temperature anomalies (SSTA) in spring, when surface heating masks the thermal signature of cyclones. This census, which documents multi-year structures and distinguishes the two regional regimes, establishes a new baseline for quantifying mesoscale transport and provides as a transferable framework for the new satellite altimetry observations (i.e., SWOT)