Geostrophic currents in the first 2000 m of the Mediterranean water column derived from Argo float data

Abstract. Extending satellite-derived surface velocities to depth in semi-enclosed basins such as the Mediterranean Sea remains challenging due to complex water mass interactions, constrained passages, and sensitivity of dynamic height calculations to numerical formulation. This study presents a three-dimensional geostrophic velocity dataset for the Mediterranean Sea (10–2000 dbar, 0.5° × 0.5°), derived from Argo float hydrography over 2001–2024 period and referenced to satellite altimetry. A specific volume anomaly formulation is adopted for relative dynamic topography, removing the dominant hydrostatic background before vertical integration and eliminating spurious deep velocity amplification inherent to conventional specific-volume approaches. The reconstructed fields resolve basin-scale gyres, boundary currents, and mesoscale eddies across the Western, Central, and Eastern Mediterranean. Validation against Copernicus Marine Service reanalysis yields root mean square differences of ~1 cm s⁻¹ above 500 dbar, decreasing to O(10⁻³) cm s⁻¹ at depth, with largest uncertainties in the intermediate layer (500–1200 dbar) where water mass boundaries intensify thermohaline gradients. The dataset provides an observation-based, three-dimensional complement to model reanalyses and is publicly available at https://doi.org/10.13120/q25v-q872.