Monitoring of the Algerian Basin circulation through glider observations, numerical simulations and altimetry during fall 2014-2016

The Algerian Basin is characterized by the presence of both fresh Atlantic waters and more saline resident Mediterranean ones that interact at different spatial and temporal scale. Rapid and energetic mesoscale structures as meanders, cyclonic and anti-cyclonic eddies, evolve from the Algerian Current that is the main large scale oceanographic feature of the area. Despite their remarkable importance, this region and its variability are still poorly known and basinwide knowledge of its mesoscale and sub-mesoscale features is still incomplete. In order to monitor such complex processes, the Algerian BAsin Circulation Unmanned Survey (ABACUS) was realized during fall 2014-2016 thanks to the support of JERICO-TNA, SOCIB external user competitive access and JERICO NEXT-TNA. A new integrated oceanographic observing system was built up in the Algerian Basin, taking advantages of the combined use of gliders, new generation satellite altimeters and numerical simulations. Our results confirm the advantages of this multi-platform strategy:  Mesoscale structures have been successfully monitored with dedicated sampling tracks during ABACUS missions; Data collection along fixed monitoring lines provided data for an interesting comparison with model data and alongtrack satellite observations in the study area;  Dynamic height calculated from glider data and satellite absolute dynamic topography present similar patterns with maximum discrepancies located nearby the Balearic Islands and the Algerian Coast;  Numerical simulations outputs agree well with the high resolution glider measurements and provide valuable information that strongly complements in situ and remote sensed observations.