This study provides for the first time estimates of sea level anomalies very close to the coastline based on high-resolution retracked altimetry data, as well as corresponding sea level trends, over a 14-year time span. This new information has so far not been provided by standard altimetry data.

The Algerian Basin plays a key role in the WMED, and the formation and propagation of mesoscale structures strongly influence its circulation. They transport water masses, heat, salts and other properties and also have an impact on chlorophyll and fisheries. We investigated the spatial and temporal distribution of the eddies by applying a detection and tracking method to altimetry data. The results show mesoscale structures with different origins, behaviours and energies.

In this work we investigate the capability of the Argo array in the Mediterranean Sea to capture mesoscale circulation structures (diameter of around 150 km). To do that we conduct several experiments to simulate different spatial sampling configurations of the Argo array in the basin. Results show that the actual Argo array in the Mediterranean (2° × 2°) might be enlarged until a spatial resolution of nearly 75 × 75 km (450 floats) in order to capture the mesoscale signal.

Spectral analyses of along-track altimetric data are used to estimate noise levels and observable ocean scales in the NW Mediterranean Sea. In winter, all altimetric missions can observe wavelengths down to 40–50 km (individual feature diameters of 20–25 km). In summer, SARAL can detect scales down to 35 km, whereas Jason-2 and CryoSat-2 with higher noise can only observe scales less than 50–55 km. Along-track altimeter data are also compared with collocated glider and coastal HF radar data.