Interactions entre turbulence et vagues à l’interface air-mer en présence de glace de mer
The Arctic summer ice cover has strongly decreased over the past decades, leaving room for more and more energetic wave systems. This makes it all the more important to understand the interactions between waves and ice in the marginal ice zone (MIZ), to improve our modeling of the Earth climate and...
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| Format: | Doctoral or Postdoctoral Thesis |
| Language: | French English |
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Université de Bretagne Occidentale
2023
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| Online Access: | https://archimer.ifremer.fr/doc/00853/96478/104824.pdf https://archimer.ifremer.fr/doc/00853/96478/ |
| Summary: | The Arctic summer ice cover has strongly decreased over the past decades, leaving room for more and more energetic wave systems. This makes it all the more important to understand the interactions between waves and ice in the marginal ice zone (MIZ), to improve our modeling of the Earth climate and prepare for future human activity in Arctic. Turbulence generated through waveice interactions is often considered to be the main driver for wave attenuation, and is modeled using the eddy viscosity hypothesis due to the lack of in-situ measurements. This thesis work consists in analysing collocated wave and turbulence measurements taken in the MIZs highly concentrated in ice of natural laboratories of the lower St. Lawrence estuary. Comparing wave energy attenuation and turbulent kinetic energy dissipation shows that, in the conditions encountered, turbulence does not allow to significantly explain wave attenuation in sea ice. Interactions between ice floes are hence quantified, and allow to explain a large part of wave attenuation in most of the cases. La couverture de glace estivale en Arctique a fortement diminué ces dernières décennies, laissant la place au développement de systèmes de vagues de plus en plus énergétiques. Ce constat rend d’autant plus importante la compréhension des interactions entre les vagues et la glace dans la zone marginale de glace (MIZ), pour améliorer notre modélisation du climat terrestre et préparer les futures activités humaine en Arctique. La turbulence générée par les interactions vague-glace est souvent considérée comme la source principale d’atténuation des vagues, et modélisé en utilisant l’hypothèse de viscosité turbulente faute de mesure in-situ. Ce travail de thèse consiste à analyser des mesures colocalisées de vagues et de turbulence prise dans des MIZs très concentrées en glace de laboratoires naturels de l’estuaire du bas Saint-Laurent. La comparaison entre l’atténuation de l’énergie des vagues, en fonction de leur propagation sous la glace, et la dissipation d’énergie ... |
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