A Four-Dimensional Survey of the Almeria–Oran Front by Underwater Gliders: Tracers and Circulation

Abstract A four-dimensional survey by a fleet of seven underwater gliders was used to identify pathways subduction at the Almeria–Oran Front in western Mediterranean Sea. The combined glider covered nearly 9000 km over ground while doing 2500 dives as deep 700 m. had sensors measure temperature, salinity, velocity, chlorophyll fluorescence, and acoustic backscatter. Data from were analyzed through objective maps that functions across-front distance, alongfront time on vertical levels separated 10 Geostrophic velocity inferred using variational approach, quasigeostrophic omega equation solved for ageostrophic horizontal velocities. Peak downward velocities near 25 m day ?1 an event propagated direction frontal jet. An examination isopycnal surface outcropped front formed showed consistency between movement tracers velocity. tended be dense side upward light so flatten manner baroclinic instability. resulting heat flux approached 80 W ?2 100-m depth with structure would cause restratification front. One track isotherm direct large 50 , net displacement 15 day.