Fronts, eddies and mesoscale circulation in the Mediterranean Sea

The Mediterranean Sea is a complex and variable ocean system. It features a wide range of temporal and spatial scales (basin, sub-basin and mesoscale, with the latter being the focus of this chapter) that interact to force a complex, highly variable general circulation. Over recent decades many oceanographic campaigns have been carried out across the Mediterranean, supported by progressively improving satellite observations (e.g., sea surface height derived from altimetry and chlorophyll concentration), with the goal of further understanding the processes and mechanisms at play. These missions typically sample sharp fronts and mesoscale eddies. More recently, these multiplatform experiments are being complemented with even wider ranges of instruments, such as gliders, drifters, underway CTDs and ADCPs. These advanced instruments enable a look beyond the mesoscale and into the submesoscale. The most exciting new instrument is the SWOT satellite, which is expected to come online sometime in 2022 and is expected to revolutionise our view of the Mediterranean, thanks to its unprecedented resolution.