Opportunity observation of an Algerian Eddy to the south of Cape Palos (southwestern Mediterranean Sea)

Large anticyclonic eddies can detach from the Algerian Current, forming open-sea Algerian Eddies. These mesoscale structures have been intensively studied by means of sea surface temperature and altimetry data, and using numerical models. However, few studies describe an in situ sampling of their whole vertical structure. Furthermore, the area extending from Cape La Nao (western edge of the Balearic Channels) to the Almeria-Oran Front has received very little attention, and it could be considered that there is a gap in our present oceanographic knowledge of this part of the western Mediterranean. An Algerian Eddy lasting for several months was detected in December 2021 to the south of Cape Palos. In order to analyse this eddy, an opportunity sampling was designed taking advantage of the periodic monitoring campaign RADMED 0222. This sampling revealed that the eddy had a baroclinic character, affecting the whole water column. These results suggest that this eddy was generated at the Algerian Current, finally affecting an area close to the eastern Spanish coast. The presence of these structures in this region of the western Mediterranean could alter the southward progression of the Northern Current and even the presence and structure of the Almeria-Oran Front.

Automated summary

This study investigates the Algerian Eddy through in situ sampling and finds that the eddy has a baroclinic character, affecting the entire water column. This discovery fills the gap in our oceanographic knowledge of this region in the western Mediterranean and provides new insights into the presence and structure of the Northern Current and the Almeria-Oran Front.