Ocean / ice sheets interactions

Titre : Ocean / ice sheets interactions

Laboratoire de rattachement : LGGE

Encadrant : Gaël Durand

Téléphone : 04.76.82.42.84

Co-Encadrant : Nicolas Jourdain

Mots clés : polar ice sheets, ice flow model Elmer/Ice

Contexte et objectifs de la mission de stage :
Recent remote sensing observations show a large acceleration of coastal outlet glaciers of both Antarctic and Greenland ice sheets. As a direct consequence of glaciers’ acceleration, mass balance of both ice sheets are currently negative, which significantly contributes to the current sea level rise. The essential driver of the observed glaciers’ recession is now clearly attributed to an increase of melting at the ocean / ice sheet interface. However, the interactions between the two systems remain poorly investigated, and representing such interactions into numerical models is a scientific challenge in which the Laboratoire de Glaciologie et de Géophysique de l’Environnement (LGGE) is now engaged.
By developing the ice flow model Elmer/Ice, the LGGE has strengthened its worldwide recognized expertise in the modeling of ice sheets in general and coastal outlet glacier dynamics in particular. LGGE also has a very proficient and accomplished oceanographic team which plays a key role in the development of the ocean general circulation model NEMO and leads its application to the Austral ocean. These two components are now being gathered together to better investigate the physical processes at the ocean / ice sheet interface and initiate the coupling of both models. During the proposed internship, a very simplified local ocean circulation model will be implemented and interfaced with Elmer/Ice at the spatial resolution of the ice flow. This will allow a better investigation of the effect of enhanced circulation and increased temperature on the ice dynamics. Conversely, we will also focus on the effect of a change in the geometry of the ice front on the ocean circulation. This will help us to better understand the possible feedbacks between the two systems and to define the strategy of coupling between Elmer/Ice and NEMO.