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Accueil > Actualités > Séminaires > Séminaires 2019

Mardi 17 décembre 2019 à 13h30 en amphi K118

Costanza Rodda, Brandenburg University of Technology, Cottbus

Titre/Title : Properties of the inertia-gravity waves emitted from jets and fronts experimentally observed in the differentially heated rotating annulus.

Contact : Nicolas Mordant (EDT)

Résumé/Abstract : Internal gravity waves are fully recognised for the relevant role they play in the atmospheric and oceanic dynamics of our planet. Over the past decades, several studies have successfully investigated generation, propaga- tion, and dissipation of gravity waves. Although many aspects are nowadays reasonably well explained, others still remain unclear and, therefore, an ac- tive research topic. One of the least understood phenomena is the emission of gravity waves from jet and front systems in the atmosphere. This work pro- poses an experimental laboratory investigation of gravity waves generated from baroclinic jets and fronts using a differentially heated rotating annulus. Gravity waves are observed along the baroclinic jet and their properties, to- gether with the conditions for emission and propagation, are examined in detail. Furthermore, the energy partition among large- and small-scale wave phenomena is investigated. The kinetic energy spectra reveal a characteristic subdivision into two distinct regimes with slopes k−3 for the large scales and k−5/3 for smaller scales resembling the atmospheric spectra. By separating the spectra into vortex and wave components, it emerges that the gravity waves observed in the experiment cause the flattering of the spectrum.