Frank Pattyn
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Frank PattynHome | C.V. | Research | Publications | Cours | Leisure | Contact |
Voici la liste des sujets de mémoire pour l'année académique 2012-2013 proposée par F. Pattyn et collaborateurs.
This study investigates the role of ice rumples and ice rises in the large-scale dynamics of Antarctic ice shelves. Ice Rises are topographic highs, which either extend the Antarctic ice-sheet seawards into the floating ice-shelves, or grounded areas within ice-shelves, that are large enough to exhibit a local flow regime. Ice rumples are small ice rises, where the flow regime is non-local and significantly influenced by the large-scale movement of the surrounding ice-shelf. Partially (or ephemeral) grounded ice rumples, are only grounded as a function of the ice-shelf's tidal uplift (grounded during low-tide, afloat during high-tide). While grounded, they act as 'pinning points' which decelerate the seaward directed ice flow. Once afloat, ice flows essentially frictionless and accelerates. The hypothesis is that observational data from partially grounded ice rumples gives insight into the (de-)buttressing effect which may play a role in defining the stability of the ice shelves.
The method encompasses the interferometric processing of sattelite SAR scences (see http://homepages.ulb.ac.be/~rdrews/research.html). InSAR is widely applicable, and also used outside the scope of polar sciences (e.g. Earthquakes, Topographic Mapping,..).
Mass loss of the Antarctic ice sheet is essentially through fast flowing glaciers which drain slow moving ice plateau towards the coast. Understanding the dynamics of such large-scale flow patterns is quintessential in future predictions of the contribution of the Antarctic ice sheet to sea-level rise. In Dronning Maud Land (East Antarctica), the Western Ragnhild Glacier is one of the biggest outlet glaciers of the region. This glacier is thought to have been stable for prolonged periods of time. The main reason for this stability is due to buttressing of the Roi Baudoin Ice Shelf, which regulate the flow from continent to ocean. This subject will aim to quantify the ice mass budget of this glacier and two others in the region by combined modelling, remote sensing and radio-echo sounding methods, based on existing databases.
The West Antarctic ice sheet is considered to be the 'weak underbelly' of the Antarctic. It is expected that increased melt rates at the grounding line (contact between grounded ice sheet and floating ice shelf) may provoke a grounding line retreat and may lead to a collapse of the ice sheet. Pine Island Glacier is currently the largest outlet glacier in Antarctica showing significant mass loss. However, the precise reason of the mass loss is not know, but most probably related to changes in the contact with the ocean. In this study, a simple flowline model of an ice sheet ice shelf system of Pine Island Glacier (West Antarctica) will be applied in order to investigate the stability of the ice sheet drained by this outlet glacier. Sensitivity experiments include changes in the melting pattern under the floating ice shelf and the glacier, changes in lubrication (basal sliding) and atmospheric effects.