The primary objective of this position is to bring about this paradigm shift by making quantitative predictions through coupled modeling using the modified GlaDS subglacial hydrology model and the Elmer/Ice ice flow model.
The research project will proceed in the following three successive stages: Stage 1: Theoretical Implementation and Synthetic Validation The first stage will consist of incorporating our physical findings into the GlaDS model by representing a distributed drainage system in which conduits and cavities are connected in series.
The candidate will be required to test and compare the predictions of this new configuration against existing theories (which model these structures in parallel) using synthetic case studies.
These numerical tests will aim to clearly isolate the impact of the driving forces by systematically varying the surface slope, the ice thickness, and the amount and variability of meltwater inflow.
Step 2: Full-scale validation on two Greenlandic glaciers The coupled hydromechanical model will then be tested and validated on a full-scale basis on two outlet glaciers in Greenland, characterized by contrasting topographic dynamics and seasonal responses: Isunguata Sermia: A glacier with a gentle surface slope and a land-terminating glacier, exhibiting marked Type 3 seasonality (winter acceleration followed by a sharp summer deceleration).
Eqip Sermia:A steeper glacier with a marine terminus, characterized by Type 2 seasonality.
In this phase, the work will focus specifically on reproducing the significant differences observed between their respective seasonal cycles.
The numerical results will be validated against the geophysical dataset acquired as part of the ERC REASSESS project (GNSS measurements and satellite imagery for horizontal velocities and ice uplift;
passive environmental seismology to locate flows and quantify subglacial water storage).
Step 3: Projections and Assessment of Long-Term Trends The final phase will consist of assessing the long-term impact of this series-distributed flow physics on the evolution of Greenland's outlet glaciers.
The researcher will use the validated model to quantify the historical and future sensitivity of Greenland's glaciers to global warming scenarios, in order to assess the extent to which the integration of slope dependence and the channel-cavity network redefines flow and mass loss trajectories on scales ranging from several decades to a century.
The Institute of Environmental Geosciences (IGE) is a public research laboratory affiliated with the CNRS, the IRD, the University of Grenoble Alpes (UGA), and Grenoble-INP.
Its research focuses on climate change and the impact of human activities on our planet in polar, mountainous, and intertropical regions—areas that are particularly sensitive to major societal challenges.
The laboratory has an average staff of approximately 330 people, including 190 permanent employees (researchers, faculty researchers, engineers, technicians, and administrative staff) and approximately 140 doctoral students, postdoctoral researchers, and contract employees.
Each year, the IGE also hosts approximately 120 interns and visiting scientists.
The IGE is spread across four buildings on the Grenoble university campus (the Glaciology Building, OSUG-B, the House of Climate and the Planet, and INRAE-Grenoble in Saint-Martin-d'Hères).
The IGE is one of the main laboratories of the Grenoble Observatory of Universe Sciences (OSUG), a federative structure of the National Institute of Universe Sciences (INSU).
The IGE actively contributes to the national research strategy in the polar regions, in collaboration with national and international partners.
It participates in numerous national and international projects.
This recruitment is part of the ERC REASSESS project led by Florent Gimbert, which aims to study the dynamics of the Greenland ice sheet in response to hydrology resulting from surface melting.
In this project, unique data acquired using fiber-optic technology were collected at the surface and within boreholes, with the goal of documenting hydrological processes, deformation, and basal friction that are otherwise difficult to access.
Analyzing this data requires the implementation of optimized processing workflows to extract relevant information and analyze it in terms of the underlying processes.
Bibliographic References for the Project • Gilbert, A., Gimbert, F., Thøgersen, K., Schuler, T.
V., & Kääb, A.
(2022).
A Consistent framework for coupling basal friction with subglacial hydrology on hard-bedded glaciers.
Geophysical Research Letters, 49(13), e2021GL097507 [1.1].
• Gimbert, F., Gilbert, A., Gagliardini, O., Vincent, C., & Moreau, L.
(2021).
Do existing theories explain seasonal to multi-decadal changes in glacier basal sliding speed?
Geophysical Research Letters, 48, e2021GL092858. • Maier, N., Gimbert, F., & Gillet-Chaulet, F.
(2022).
Threshold response to melt drives large-scale bed weakening in Greenland.
Nature, 607(7920), 714–720. • Schoof, C.
(2010).
Ice-sheet acceleration driven by melt supply variability.
Nature, 468(7325), 803–806. • Zeller, M., Gilbert, A., Gimbert, F., et al.
Détermination de la loi de frottement à la base des glaciers à partir d'observations à l'échelle multidécennale et centenaire des variations de vitesse de surface et d'épaisseur sur les glaciers alpins.
Soumis au *Journal of Geophysical Research*.
• Zeller, M., Gimbert, F., Gilbert, A., et al.
La saisonnalité de l'écoulement en fonction de la pente révèle les mécanismes régissant la dynamique glaciaire à long terme.
Soumis / Prépublication.