October 22, 2021
16 h
Auditoire MERC02, Place Louis Pasteur, 3
The exchanges between the ocean, cryosphere, and atmosphere in the Southern Ocean play a pivotal role in the Earth’s Climate by driving the storage and redistribution of heat, freshwater, and CO2. However, our understanding of the processes at play is limited due to the scarcity of in-situ observations. Besides, climate models disagree on the future of Antarctica and appear to misrepresent the current trends. Is there something we are missing?
Small-scale processes might be an answer. These processes, which take place at scales smaller than 100 km, are particularly hard to observe and cannot be explicitly resolved by most climate models. In this thesis, we explore their role in the interactions between the ocean, cryosphere, and atmosphere using high-resolution numerical models. The focus is given to the Adélie Land sector, one of the few birthplaces of the Antarctic Bottom Water which fills the depths of the World Ocean. The influences of ocean-ice shelf interactions, ocean tides, small-scale katabatic winds, and mesoscale eddies in ocean-cryosphere-atmosphere interactions are investigated. We show that, despite their small spatial scales, these processes have non-negligible effects on sea ice production and transport, water masses transformations, and on the exchanges of heat, freshwater, and momentum between the ocean, cryosphere, and atmosphere. Our results suggest that these processes could have important implications for the dynamics of the Antarctic climate and the way it will responds to the anthropogenic forcing. This thesis improves our understanding of rarely observed processes and stresses the need to incorporate them in climate models.