Cuypers Y. auteur aut IRD Bouruet-Aubertot P. auteur aut IRD Vialard Jérôme auteur aut IRD McPhaden M. J. auteur aut IRD text journalArticle eng text/pdf born digital access The refraction of internal waves by lower-frequency near-inertial waves has been predicted theoretically, but never observed before. Here, we report observations of semi-diurnal internal tides generated by the rough topography of the Central Indian Ridge, in the presence of a strong, lower-frequency near-inertial wave field generated by a tropical storm. The semi-diurnal internal tide energy is trapped within upward propagating bands with a periodicity close to the inertial period. A ray-tracing model suggests that this trapping results from the internal tide refraction by the shear associated with near-inertial waves. This yields a strong increase of the internal tide energy and shear in space-time regions where the background flow focuses the rays, leading to the formation of caustics. This mechanism may increase vertical mixing generated by baroclinic tides in the vicinity of mid-ocean ridges in tropical regions. specialized OCEAN INDIEN ZONE TROPICALE 032 44 5 2398-2406 2017 0094-8276 https://www.documentation.ird.fr/hor/fdi:010069421 10.1002/2017gl072625 0094-8276 [F B010069421] https://www.documentation.ird.fr/hor/fdi:010069421 https://www.documentation.ird.fr/intranet/publi/2017/04/010069421.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2017-05-09 2023-07-11 fdi:010069421 fre