Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Journal of Physical Oceanography 631-646 PEROU 2013 fdi:010060842 ENG Journal of Physical Oceanography 0022-3670 ISI:000317114800010 3 10.1175/jpo-d-12-035.1 https://www.documentation.ird.fr/hor/fdi:010060842 https://www.documentation.ird.fr/intranet/publi/2013/05/010060842.pdf 43 Horizon (IRD) The upwelling system off southern Peru has been observed using an autonomous underwater vehicle (a Slocum glider) during October-November 2008. Nine cross-front sections have been carried out across an intense upwelling cell near 148 degrees S. During almost two months, profiles of temperature, salinity, and fluorescence were collected at less than 1-km resolution, between the surface and 200-m depth. Estimates of alongshore absolute geostrophic velocities were inferred from the density field and the glider drift between two surfacings. In the frontal region, salinity and biogeochemical fields displayed cross-shore submesoscale filamentary structures throughout the mission. Those features presented a width of 10-20 km, a vertical extent of; 150 m, and appeared to propagate toward the shore. They were steeper than isopycnals and kept an aspect ratio close to f/N, the inverse of the Prandtl ratio. These filamentary structures may be interpreted mainly as a manifestation of submesoscale turbulence through stirring of the salinity gradients by the mesoscale eddy field. However, meandering of the front or cross-frontal wind-driven instabilities could also play a role in inducing vertical velocities. 032 UR182 / UR065 Pérou