Description du sujet de thèse

The EAU-SPRA project at ITES deals with the hydrological model NIHM, which has been developed in-house for about ten years by the Transferts dans les Hydrosystèmes Continentaux (TrHyCo) team at the Institute for Erath and Environment of Strasbourg. It is composed of two different modules - one that determines recharge by performing water and energy balances in surface compartments, and a second that describes flows in groundwater and the hydrographic network - and has been applied to several real systems.
The aim of this thesis is to develop, implement and test an automatic calibration approach for the NIHM model. This approach should make it possible to minimize an objective function measuring the quadratic deviation between observations - water level in the river and/or piezometric level - and simulations, by adjusting the model's most influential parameters. More specifically, the person in charge of this work will have to:
I. Become familiar with the NIHM model
II. Become familiar with automatic calibration methods, and more specifically with the approaches already used in the team in different contexts - i.e. adjoint-state methods, use of meta-models, etc. The person recruited will be able to use existing tools on simple cases to better understand the basic concepts.
III. Develop and implement the chosen automatic calibration approach. It can then be tested on a synthetic case.
IV. Apply this approach to a real case, to be chosen according to data availability and associated computation time.

Contexte de travail

Physically-based hydrologic models describe all possible flow processes in watersheds, integrating the interactions between the main compartments, i.e. the subsurface, the topographic surface, vegetation and the atmosphere. This type of model has been developed in the community since the early 2000s. They are now considered as relevant tools for addressing a wide range of issues relating to the management of surface and/or groundwater bodies. It is in this context that the EAU-SPRA project was funded by ADEME (French Environment and Energy Agency). The aim of this project - carried out in collaboration between ANTEA Group, Mines de Paris and the Institute for Erth and Anvironement of Strasbourg (ITES) - is to develop a platform based on the results of several hydrological models, enabling managers and major users to visualize the quantitative evolution of water bodies in their territory in a relatively simple way. Three scientific challenges have been identified to enable the development of such a platform: uncertainty quantification, automatic calibration and change of scale. The proposed doctoral project falls within this general framework.
Expected training and skills:
Master's degree in Water Sciences, Geosciences or mathematics applied to modeling OR Engineering degree in Water, Environment or Geosciences.
Advanced skills expected in applied mathematics, environmental modeling and programming (Python or Fortran). Basic skills in hydrology and hydrogeology are essential.
Keen interest in computer programming. Enthusiasm and motivation to work on the development and application of numerical codes.
Other skills required: skills in statistics and applied mathematics / ability to read and write in English / ability to work in a team / ability to communicate scientific results / ability to interact with non-scientists.
Working Environment:
The Institute for Earth and Environment of Strasbourg (ITES) is a Joint Research Unit (UMR-7063) under the auspices of the CNRS, the University of Strasbourg and ENGEES. This UMR is based on 4 disciplines to study the Earth and its surface environment: hydrology, geochemistry, geology and geophysics. ITES has 6 research teams. The work for this thesis will be carried out in the “Transfer in continental hydrosystems” team, which studies transfer processes in hydrological systems in the broadest sense, using modeling approaches (methodological developments and/or applications) or experimental approaches. The team's research focuses in particular on the qualitative and quantitative evolution of water bodies, transfer processes in the soil-plant-atmosphere continuum, transfer processes in complex systems, and the modeling of couplings between water flow, transport of elements and/or heat and mechanics.

Contraintes et risques

Constraints related to field trips