Three Decades of Levantine Sea Dynamics: A High-Resolution Modelling Perspective

The physical dynamics of the Eastern Mediterranean Sea remain challenging to characterize, particularly in the marginal Levantine Sea, where steep continental slopes, narrow shelves, and intense mesoscale and submesoscale activity shape a highly complex coastline. To advance our understanding of circulation in these coastal and shelf environments, we present a new high-resolution regional hydrodynamic model for the Levantine Sea that resolves dominant circulation features, including boundary currents, margin-intensified flows, and dynamically active coastal regions.

Built on the NEMO 3.6 ocean model with a horizontal resolution of 2.2 km and 71 vertical levels, the simulation incorporates realistic atmospheric forcing, river inflows, and carefully tuned open-boundary conditions to ensure physically consistent behaviour over three decades (1992–2022). The model reproduces major seasonal patterns and mixed-layer evolution documented by regional monitoring systems and captures the long-term sea-surface thermal intensification in the basin. Over the 31-year hindcast, temperature trends show a persistent rise in warm anomalies, especially in autumn and winter, consistent with satellite-based assessments of climate-driven heating in the region.

In this study, we emphasize the formation and export of Levantine Intermediate Water (LIW). Beyond the well-established formation in the Rhodes Gyre, the model reveals intermittent intermediate-water production along the continental slopes of the Gulf of Antalya and the Cilician Basin, a feature increasingly recognized by recent research. The extended hindcast further quantifies LIW transport variability through the boundary current, highlighting phases of enhanced outflow, internal recirculation, and quasi-stagnant periods modulated by stratification and wind-driven variability.

The model provides a reproducible platform for investigating circulation processes central to the semi-enclosed Levantine Sea, including boundary-current characteristics, eddy–slope interactions, episodic water-mass formation, and the sensitivity of coastal circulation to atmospheric forcing and long-term thermal changes. It complements regional observational efforts and offers a foundation for future coastal-process studies and operational applications.