Description of the thesis topic

Thesis topic: DesertLakes-4D - Modelling the hydro-climatic variability of lakes in arid zones.

Missions :
In the context of current climate change, lakes in arid zones are facing imminent threats due to their dependence on a very fragile water balance. Global warming is expected to have an uncertain impact on lakes over the next century, with an increase in the frequency and intensity of precipitation on the one hand, and an increase in evaporation on the other. This PhD project will focus on modelling the evolution of Lake Eyre-Kati Thanda. The mechanisms and interactions between the climate and the lake in an endoreic catchment will be explored in particular. The seasonal, interannual and multiannual variability of atmospheric parameters (precipitation, evaporation, runoff and wind) will be studied in depth in different climatic contexts.
The candidate will have to produce a modern reference case aimed at simulating variations in Lake Eyre-Kati Thanda using ERA5land meteorological reanalyses. To study the evolution of the lake in other climatic contexts, climate simulations carried out with the IPSL-CM6 Earth System Model (ESM) will be used. The simulation of the evolution of the lake forced by a simulation of the current climate carried out with an ESM will be compared with that obtained with meteorological reanalyses in order to identify any biases. This analysis will then be extended to estimating the lake's response to various future climate projections, as well as identifying critical periods during the last glacial/interglacial cycle, when Lake Eyre-Kati Thanda was transformed into a mega-lake. These different scenarios make it possible to understand the hydrological response of the basin over a broad climatic spectrum and to estimate the possible feedback mechanisms of the lake on the climate.
By examining the response of Lake Eyre-Kati Thanda to these different scenarios, we have a modern analogue for understanding the climate message conveyed by lake sediment archives in an arid to semi-arid context. To achieve this, a geochemical component model will be added to the lake model to simulate the evaporitic deposits of Eyre-Kati Thanda and better constrain the dynamics of palaeolacustrine systems and their response to extreme events intrinsically associated with current and past climate change.

Activities:
The candidate will be responsible for completing the development of the tools required for the study. He/she will carry out the necessary numerical simulations and analyse the results. The results obtained will be presented at conferences. The results should be published in high-impact scientific journals.

Work Context

A world-renowned geosciences research institute founded in 1921, associated with the CNRS, a component of Université Paris Cité and employing over 500 people, the IPGP covers all the disciplines of earth and planetary sciences through observation, experimentation and modelling, on all scales of time and space.
The research themes are structured around 4 major unifying themes: the interior of the Earth and planets, natural hazards, the Earth system and origins.
The IPGP is also responsible for accredited services in volcanology, seismology, magnetism, gravimetry and erosion. In particular, the IPGP's permanent observatories monitor the 4 active French overseas volcanoes in Guadeloupe, Martinique, Réunion and Mayotte (REVOSIMA).
The IPGP houses powerful computing resources and state-of-the-art experimental and analytical facilities, and benefits from first-rate technical support.
The IPGP's training and doctoral studies department offers its students training in the geosciences that combines observation, quantitative analysis and modelling and reflects the quality, richness and thematic diversity of the research carried out by the IPGP's teams.


The first part of the thesis will be carried out within the IPGP palaeomagnetism team. This team is made up of 8 researchers and a research engineer. The team is conducting a research programme on subjects as varied as the evolution of the Earth's magnetic field, geodynamics and environmental magnetism, as well as climate change and biogeochemical cycles on different timescales. The team's research activities are based on magnetic measurement and characterisation, experimentation and numerical modelling.
This thesis work will continue at the School of Geography, Earth and Atmospheric Sciences at the University of Melbourne (Australia). This institution has an active programme in key areas of research into earth surface processes. These range from fluvial geomorphology, river management and environmental reconstruction to palaeoclimatology, the development of dating techniques and neotectonics in the School of Geography, Earth and Atmospheric Sciences.

Constraints and risks

Travel in France and stay in Australia for about a year (University of Melbourne).

Additional Information

- Specific training: Geosciences or physics, knowledge of atmospheric/ocean/climate sciences and/or hydrogeology. A good command of English is essential (part of the thesis will take place in Australia) - advanced B2 level required,
- IT tools: knowledge of programming (Fortran and/or C language), Python, Unix,
- Professional qualities: rigorous, with a taste for computer programming.