Laboratory modelling of momentum transport by internal gravity waves and eddies in the Antarctic circumpolar current

• Main Authors: Sommeria, Joël, Ajayi, Adekunle-Opeoluwa, Raja, Keshav Jayakrishnan, Staquet, Chantal, Viboud, Samuel, Voisin, Bruno
• Other Authors: Laboratoire des Écoulements Géophysiques et Industriels Grenoble (LEGI ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 )
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2016
• Subjects: [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph]; Antarctic; The Antarctic; Antarc*
• Online Access: https://hal.archives-ouvertes.fr/hal-01648235; https://hal.archives-ouvertes.fr/hal-01648235/document; https://hal.archives-ouvertes.fr/hal-01648235/file/16CIRCUMPOLAR_issf.pdf

International audience The Antarctic Circumpolar current is recognized as a key location for ocean mixing, and its interaction with the bottom topography is an important source of energy dissipation and mixing. We have reproduced this process in a linearly stratified fluid on the Coriolis rotating platform, 13 m in diameter. A uniform circular current around the tank is produced by a small change of tank rotation speed (spinup) which persists by inertia for the duration of the experiment. The wake of a single spherical cap is first investigated, involving wave emission and vortex shedding. Then a bottom roughness is introduced as a set of 18 spherical caps. In the absence of background rotation, the friction effect on the current is mainly confined to the wake located below the topography top, with a weak contribution of the radiated lee waves. By contrast, the background rotation favors the downward transport of momentum by mechanisms that we relate to the excitation of inertial waves and Ekman pumping enhanced by the rough bottom.