Soutenance de Brivaël Collin
| When |
Mar 20, 2026
from 02:00 to 04:00 |
|---|---|
| Where | Salle des thèses |
| Attendees |
Brivaël Collin |
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Climate change is warming the oceans, but its impact on polar ice-shelf melting remains uncertain. Ice shelves, floating extensions of continental glaciers, lose a large part of their mass through heat transfer from underlying seawater, making the ice–ocean boundary layer critical to ice-sheet evolution. This thesis investigates ice–ocean interaction in laboratory experiments: a slab of freshwater ice is immersed in a heated saltwater tank. Shadowgraphy measures melt rates, particle image velocimetry (PIV) captures flow fields, and probes record vertical temperature and salinity profiles.
Melting generates a cold, fresh layer beneath the ice, whose stability, quantified by the density ratio Rρ, controls heat transfer. When Rρ <<1, convection disrupts the layer and accelerates melting; when Rρ >> 1, the stratified layer limits heat flux. Typically, a two-layer structure forms, and low salinity can destabilize it, increasing melt rates. By linking high-resolution flow and thermohaline measurements to melting regimes, this study provides quantitative insight into ice-shelf stability and their sensitivity to ocean warming, improving predictions of potential sea-level contributions.